Minor PyPi and Xcode related fixes

Author: ochubar

.github/workflows/pypi_publish.yml

@@ -165,6 +165,7 @@ jobs:
         with:
           #name: wheels
           path: dist/
+          merge-multiple: true
 
       - name: Publish wheels to PyPI
         uses: pypa/gh-action-pypi-publish@release/v1

cpp/gcc/Makefile

@@ -26,6 +26,7 @@ else
 		OSFLAG += -D__MAC__
 		CC  ?= gcc
 		CXX ?= g++ -stdlib=libc++ -mmacosx-version-min=10.9
+		export CPLUS_INCLUDE_PATH=/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1
 	endif
 endif