fix: Add -fPIC option for building C guests. (#421)

I ran into an issue running `just guests` on Fedora 41, and adding the -fPIC option
in the C flags fixes this.

Signed-off-by: Pranoy Dutta <[email protected]>

Author: prydt

c.just

@@ -9,7 +9,7 @@ c-flags-release-pe := '/O2 /Gy'
 
 # Elf options
 # We don't support stack protectors at the moment, but Arch Linux clang auto-enables them for -linux platforms, so explicitly disable them.
-c-compile-options-elf := '-nobuiltininc -H --target=x86_64-unknown-linux-none -fno-stack-protector -fstack-clash-protection -mstack-probe-size=4096'
+c-compile-options-elf := '-nobuiltininc -H --target=x86_64-unknown-linux-none -fno-stack-protector -fstack-clash-protection -mstack-probe-size=4096 -fPIC'
 c-include-flags-elf := replace(c-include-flags-pe, '/I ', '-I ')
 c-linker-options-elf := '--entry "entrypoint" --nostdlib -pie'
 c-flags-debug-elf := '-O0'