Support compiling GCC 2.95

Author: Kartatz

.github/workflows/build.yml

@@ -12,7 +12,7 @@ permissions: write-all
 env: 
     OBGGCC_BUILD_PARALLEL_LEVEL: 40
     OBGGCC_BUILD_DIRECTORY: /tmp
-    OBGGCC_RELEASE: '16'
+    OBGGCC_RELEASE: '2.95'
     OBGGCC_TARGETS: '*'
 
 jobs:
@@ -42,6 +42,9 @@ jobs:
     - name: Build OBGGCC
       if: ${{ steps.check-cache.outputs.cache-hit != 'true' }}
       run: |
+        if [ "${OBGGCC_RELEASE}" = '2.95' ]; then
+              export OBGGCC_BUILD_PARALLEL_LEVEL='1'
+        fi
         zsh './build.sh'
     - name: Generate tarball
       if: ${{ steps.check-cache.outputs.cache-hit != 'true' }}
@@ -143,7 +146,7 @@ jobs:
         source './tools/setup_toolchain.sh'
         
         if [[ '${{ matrix.target }}' = *'-linux-musl'* ]]; then
-            declare -r RAIDEN_TAG='gcc-15'
+            declare -r RAIDEN_TAG='gcc-16'
             declare -r RAIDEN_TARBALL='/tmp/toolchain.tar.xz'
             declare -r RAIDEN_URL="https://github.com/AmanoTeam/musl-gcc-cross/releases/download/${RAIDEN_TAG}/x86_64-unknown-linux-gnu.tar.xz"
             
@@ -183,7 +186,7 @@ jobs:
             
             source "${LOKI_HOME}/build/autotools/${{ matrix.target }}.sh"
         elif [[ '${{ matrix.target }}' = *'-netbsd'* ]]; then
-            declare -r DAKINI_TAG='gcc-15'
+            declare -r DAKINI_TAG='gcc-16'
             declare -r DAKINI_TARBALL='/tmp/toolchain.tar.xz'
             declare -r DAKINI_URL="https://github.com/AmanoTeam/netbsd-gcc-cross/releases/download/${DAKINI_TAG}/x86_64-unknown-linux-gnu.tar.xz"
             
@@ -244,6 +247,10 @@ jobs:
             source "${DARWIN_HOME}/build/autotools/${{ matrix.target }}.sh"
         fi
         
+        if [ "${OBGGCC_RELEASE}" = '2.95' ]; then
+              export OBGGCC_BUILD_PARALLEL_LEVEL='1'
+        fi
+        
         zsh './build.sh'
     - name: Create logs
       if: always()

build.sh

@@ -627,12 +627,19 @@ if ! [ -f "${gcc_tarball}" ]; then
 
 	if (( gcc_major >= 4.0 && gcc_major <= 4.2 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-4.0/0001-Add-host-support-for-x64-MinGW.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Add-host-support-for-x64-MinGW.patch"
 	elif (( gcc_major <= 3.3 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Add-host-support-for-x64-MinGW.patch"
 	elif (( gcc_major <= 3.4 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.4/0001-Add-host-support-for-x64-MinGW.patch"
 	fi
 
+	if (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Add-host-support-for-x86_64.patch"
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Restore-source-files-with-stripped-license-headers.patch"
+	fi
+
 	if (( gcc_major == 11 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-11/0001-Unpoison-calloc-on-musl-hosts.patch"
 	fi
@@ -653,6 +660,8 @@ if ! [ -f "${gcc_tarball}" ]; then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-5/0001-Fix-definition-of-abort-on-Windows.patch"
 	elif (( gcc_major >= 3.4 && gcc_major <= 4.9 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.4/0001-Fix-definition-of-abort-on-Windows.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Fix-definition-of-abort-on-Windows.patch"
 	elif (( gcc_major <= 3.3 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Fix-definition-of-abort-on-Windows.patch"
 	fi
@@ -667,6 +676,11 @@ if ! [ -f "${gcc_tarball}" ]; then
 
 	if (( gcc_major <= 4.9 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-strerror.c-Do-not-declare-sys_nerr-or-sys_errlist-if-already-macros.patch"
+	fi
+	
+	if (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Avoid-incorrectly-declaring-the-caddr_t-alias-on-Linux.patch"
+	elif (( gcc_major <= 4.9 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Avoid-incorrectly-declaring-the-caddr_t-alias-on-Linux.patch"
 	fi
 
@@ -682,18 +696,26 @@ if ! [ -f "${gcc_tarball}" ]; then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Allow-compilation-with-GCC-4.4-and-up.patch"
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Fix-redeclaration-error.patch"
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Fix-locale-support-for-glibc-2.3.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Allow-compilation-with-GCC-4.4-and-up.patch"
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Fix-redeclaration-error.patch"
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Fix-locale-support-for-glibc-2.3.patch"
 	fi
 
 	if (( gcc_major >= 3.1 && gcc_major <= 3.2 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Don-t-error-out-for-unknown-platforms.patch"
 	elif (( gcc_major == 3.3 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.3/0001-Don-t-error-out-for-unknown-platforms.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Don-t-error-out-for-unknown-platforms.patch"
 	fi
 
 	if (( gcc_major >= 3.3 && gcc_major <= 3.4 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-${gcc_major}/0001-Handle-enable-checking-release.patch"
 	elif (( gcc_major >= 3.1 && gcc_major <= 3.2 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Handle-enable-checking-release.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Handle-enable-checking-release.patch"
 	fi
 
 	if (( gcc_major >= 4.5 && gcc_major <= 4.8 )); then
@@ -704,6 +726,8 @@ if ! [ -f "${gcc_tarball}" ]; then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Add-missing-_attribute__-__gnu_inline__.patch"
 	elif (( gcc_major == 3.3 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.3/0001-Add-missing-_attribute__-__gnu_inline__.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Add-missing-_attribute__-__gnu_inline__.patch"
 	fi
 
 	if (( gcc_major >= 4.1 && gcc_major <= 4.7 )); then
@@ -714,6 +738,8 @@ if ! [ -f "${gcc_tarball}" ]; then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Disable-building-documentation.patch"
 	elif (( gcc_major == 3.3 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.3/0001-Disable-building-documentation.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Disable-building-documentation.patch"
 	fi
 
 	if (( gcc_major >= 4.2 && gcc_major <= 4.4 )); then
@@ -734,6 +760,8 @@ if ! [ -f "${gcc_tarball}" ]; then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-${gcc_major}/0001-Prevent-use-of-_unlocked-functions-and-disable-inclusion-of-malloc.h.patch"
 	elif (( gcc_major >= 3.1 && gcc_major <= 3.3 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0001-Prevent-use-of-_unlocked-functions-and-disable-inclusion-of-malloc.h.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0001-Prevent-use-of-_unlocked-functions-and-disable-inclusion-of-malloc.h.patch"
 	fi
 
 	if (( gcc_major == 6 )); then
@@ -777,6 +805,8 @@ if ! [ -f "${gcc_tarball}" ]; then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-6/0007-Add-relative-RPATHs-to-GCC-host-tools.patch"
 	elif (( gcc_major >= 3.1 && gcc_major <= 3.3 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0007-Add-relative-RPATHs-to-GCC-host-tools.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0007-Add-relative-RPATHs-to-GCC-host-tools.patch"
 	else
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-${gcc_major}/0007-Add-relative-RPATHs-to-GCC-host-tools.patch"
 	fi
@@ -793,6 +823,8 @@ if ! [ -f "${gcc_tarball}" ]; then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-${gcc_major}/0010-Prefer-DT_RPATH-over-DT_RUNPATH.patch"
 	elif (( gcc_major >= 3.1 )); then
 		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-3.1/0010-Prefer-DT_RPATH-over-DT_RUNPATH.patch"
+	elif (( gcc_major == 2.95 )); then
+		patch --directory="${gcc_directory}" --strip='1' --input="${workdir}/patches/gcc-2.9/0010-Prefer-DT_RPATH-over-DT_RUNPATH.patch"
 	fi
 
 	if (( gcc_major == 3.1 )); then
@@ -1183,6 +1215,10 @@ if (( gcc_major <= 4.0 )); then
 	targets=("${(@)targets:#arm-unknown-linux-gnueabi}")
 fi
 
+if (( gcc_major <= 3.0 )); then
+	targets=("${(@)targets:#x86_64-unknown-linux-gnu}")
+fi
+
 for target in "${targets[@]}"; do
 	check_target_exists "${gcc_targets}" "${target}" || continue
 
@@ -1302,6 +1338,18 @@ for target in "${targets[@]}"; do
 		cp "${binutils_gnu_wrapper}" "${bin}"
 	done
 
+	if (( gcc_major == 2.95 )); then
+		# This version of GCC looks up the target's system headers in
+		# '<tooldir>/bin/include' (the C-preprocessor adds '/include'
+		# to every -B directory it was started with)
+		ln \
+			--symbolic \
+			--relative \
+			--force \
+			"${toolchain_directory}/${triplet}/include" \
+			"${toolchain_directory}/${triplet}/bin/include"
+	fi
+	
 	rm --force --recursive "${PWD}"
 
 	if (( gcc_major >= 6 )) && ( [ "${triplet}" = 'x86_64-unknown-linux-gnu' ] || [ "${triplet}" = 'i386-unknown-linux-gnu' ] ); then
@@ -1461,10 +1509,18 @@ for target in "${targets[@]}"; do
 		unlink "${toolchain_directory}/${triplet}/usr"
 	fi
 
-	if (( gcc_major <= 4.1 )); then
+	if (( gcc_major >= 3.0 && gcc_major <= 4.1 )); then
+		# GCC 2.95 keeps its C++ headers in '<prefix>/include/g++-3',
+		# whose path is hard-coded into the compiler
 		mv \
 			"${toolchain_directory}/include/c++" \
 			"${toolchain_directory}/${triplet}/include"
+	elif (( gcc_major == 2.95 )); then 
+		mkdir --parent "${toolchain_directory}/${triplet}/include/c++"
+		
+		mv \
+			"${toolchain_directory}/include/g++-3" \
+			"${toolchain_directory}/${triplet}/include/c++/${gcc_major}"
 	fi
 
 	if (( gcc_major <= 3.3 )); then
@@ -1497,11 +1553,13 @@ for target in "${targets[@]}"; do
 			"${toolchain_directory}/lib/gcc/${triplet}/${gcc_major}."* \
 			"${toolchain_directory}/lib/gcc/${triplet}/${gcc_major}"
 
-		ln \
-			--symbolic \
-			--relative \
-			"${toolchain_directory}/${triplet}/include/c++/${gcc_major}."* \
-			"${toolchain_directory}/${triplet}/include/c++/${gcc_major}"
+		if (( gcc_major >= 3.0 )); then
+			ln \
+				--symbolic \
+				--relative \
+				"${toolchain_directory}/${triplet}/include/c++/${gcc_major}."* \
+				"${toolchain_directory}/${triplet}/include/c++/${gcc_major}"
+		fi
 	fi
 
 	if (( gcc_major >= 4.3 && gcc_major <= 11 )); then
@@ -1526,6 +1584,22 @@ for target in "${targets[@]}"; do
 		cd '../lib'
 	fi
 
+	if (( gcc_major == 2.95 )); then
+		ln \
+			--symbolic \
+			--relative \
+			--force \
+			'libstdc++-libc6.1-2.so.3' \
+			'libstdc++.so'
+		
+		ln \
+			--symbolic \
+			--relative \
+			--force \
+			'libstdc++-3-libc6.1-2-2.10.0.a' \
+			'libstdc++.a'
+	fi
+	
 	"${triplet}-strip" "${PWD}/lib"*'.so' 2>/dev/null || true
 
 	if (( gcc_major >= 13 && gcc_major <= 15 )); then
@@ -1542,6 +1616,10 @@ for target in "${targets[@]}"; do
 			LDFLAGS="${linkflags}"
 	fi
 
+	if (( gcc_major == 2.95 )); then 
+		rm "${toolchain_directory}/lib/gcc/${triplet}/${gcc_major}/libstdc++"*
+	fi
+	
 	ln \
 		--symbolic \
 		--relative \
@@ -1595,7 +1673,9 @@ for target in "${targets[@]}"; do
 		cp "${toolchain_directory}/bin/${triplet}-g++${exe}" "${toolchain_directory}/bin/${triplet}-c++${exe}"
 	fi
 
-	cat "${workdir}/patches/c++config.h" >> "${toolchain_directory}/${triplet}/include/c++/${gcc_major}/${triplet}/bits/c++config.h"
+	if (( gcc_major >= 3.0 )); then
+		cat "${workdir}/patches/c++config.h" >> "${toolchain_directory}/${triplet}/include/c++/${gcc_major}/${triplet}/bits/c++config.h"
+	fi
 
 	if (( gcc_major >= 4.6 )); then
 		if [[ "${host}" = *'-mingw32' ]]; then
@@ -1889,6 +1969,10 @@ while read item; do
 		continue
 	fi
 
+	if (( gcc_major <= 3.0 )) && [[ "${triplet}" = 'x86_64-'* ]]; then
+		continue
+	fi
+	
 	declare repository="$(jq --raw-output '.repository.url' <<< "${item}")"
 	declare release="$(jq --raw-output '.repository.release' <<< "${item}")"
 	declare resource="$(jq --raw-output '.repository.resource' <<< "${item}")"
@@ -2213,3 +2297,4 @@ if ( find "${toolchain_directory}" -xtype 'l' -print -quit | grep -q . ); then
 fi
 
 cp "${workdir}/README.md" "${toolchain_directory}"
+

patches/gcc-2.9/0001-Add-host-support-for-x64-MinGW.patch

@@ -0,0 +1,57 @@
+From 0751a06c08a0585fcdb7c22346527702f698f1a5 Mon Sep 17 00:00:00 2001
+From: Kartatz <105828205+Kartatz@users.noreply.github.com>
+Date: Sat, 8 Aug 2026 18:02:39 +0000
+Subject: [PATCH] Add host support for x64 MinGW
+
+---
+ gcc/configure    | 4 ++--
+ gcc/configure.in | 4 ++--
+ 2 files changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/gcc/configure b/gcc/configure
+index 38d3db4fe27..4ca45c280fe 100755
+--- a/gcc/configure
++++ b/gcc/configure
+@@ -3866,7 +3866,7 @@ for machine in $build $host $target; do
+ 		fi
+ 		exeext=.exe
+ 		;;
+-	i[34567]86-*-pe | i[34567]86-*-cygwin*)
++	*-*-pe | *-*-cygwin*)
+ 		xm_file="${xm_file} i386/xm-cygwin.h"
+ 		tmake_file=i386/t-cygwin
+ 		tm_file=i386/cygwin.h
+@@ -3877,7 +3877,7 @@ for machine in $build $host $target; do
+ 		fi
+ 		exeext=.exe
+ 		;;
+-	i[34567]86-*-mingw32*)
++	*-*-mingw32*)
+ 		tm_file=i386/mingw32.h
+ 		xm_file="${xm_file} i386/xm-mingw32.h"
+ 		tmake_file="i386/t-cygwin i386/t-mingw32"
+diff --git a/gcc/configure.in b/gcc/configure.in
+index 55dcec76823..f2fe9e8220b 100644
+--- a/gcc/configure.in
++++ b/gcc/configure.in
+@@ -1527,7 +1527,7 @@ changequote([,])dnl
+ 		exeext=.exe
+ 		;;
+ changequote(,)dnl
+-	i[34567]86-*-pe | i[34567]86-*-cygwin*)
++	*-*-pe | *-*-cygwin*)
+ changequote([,])dnl
+ 		xm_file="${xm_file} i386/xm-cygwin.h"
+ 		tmake_file=i386/t-cygwin
+@@ -1540,7 +1540,7 @@ changequote([,])dnl
+ 		exeext=.exe
+ 		;;
+ changequote(,)dnl
+-	i[34567]86-*-mingw32*)
++	*-*-mingw32*)
+ changequote([,])dnl
+ 		tm_file=i386/mingw32.h
+ 		xm_file="${xm_file} i386/xm-mingw32.h"
+-- 
+2.54.0
+

patches/gcc-2.9/0001-Add-host-support-for-x86_64.patch

@@ -0,0 +1,45 @@
+From 5e70008857be1b4554334fbb58f8ef67d37618ea Mon Sep 17 00:00:00 2001
+From: Kartatz <105828205+Kartatz@users.noreply.github.com>
+Date: Sat, 8 Aug 2026 21:20:44 +0000
+Subject: [PATCH] Add host support for x86-64
+
+---
+ gcc/configure    | 5 +++++
+ gcc/configure.in | 5 +++++
+ 2 files changed, 10 insertions(+)
+
+diff --git a/gcc/configure b/gcc/configure
+index 38d3db4fe27..a2c5906864c 100755
+--- a/gcc/configure
++++ b/gcc/configure
+@@ -2947,6 +2947,11 @@ for machine in $build $host $target; do
+ 	sparc*-*-*)
+ 		cpu_type=sparc
+ 		;;
++	x86_64*-*-*)
++		# x86-64 is the 64-bit extension of the i386 architecture; use the
++		# i386 host configuration for x86-64 hosts.
++		cpu_type=i386
++		;;
+ 	esac
+ 
+ 	tm_file=${cpu_type}/${cpu_type}.h
+diff --git a/gcc/configure.in b/gcc/configure.in
+index 55dcec76823..e3e7f4738ee 100644
+--- a/gcc/configure.in
++++ b/gcc/configure.in
+@@ -513,6 +513,11 @@ changequote([,])dnl
+ 	sparc*-*-*)
+ 		cpu_type=sparc
+ 		;;
++	x86_64*-*-*)
++		# x86-64 is the 64-bit extension of the i386 architecture; use the
++		# i386 host configuration for x86-64 hosts.
++		cpu_type=i386
++		;;
+ 	esac
+ 
+ 	tm_file=${cpu_type}/${cpu_type}.h
+-- 
+2.54.0
+