Use CXXFLAGS instead of CFLAGS for linking C++ code

Otherwise, this would break if using C and C++ compilers from
different families and they understand different options.  It already
used the right flags for compiling, this is only for linking.  Also,
the meson setup already did this correctly.

Back-patch of v18 commit 365b5a345 into older supported branches.
At the time we were only aware of trouble in v18, but as shown
by buildfarm member siren, older branches can hit the problem too.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Author: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://www.postgresql.org/message-id/228700.1722717983@sss.pgh.pa.us
Discussion: https://postgr.es/m/3109540.1771698685@sss.pgh.pa.us
Backpatch-through: 14-17

diff --git a/src/backend/jit/llvm/Makefile b/src/backend/jit/llvm/Makefile
index 1c3022b627415204cbd369869c6e926219758ce1..13d9d7c6256989bc78e8134fcb0439c98a7314b9 100644 (file)
--- a/src/backend/jit/llvm/Makefile
+++ b/src/backend/jit/llvm/Makefile
@@ -39,7 +39,7 @@ SHLIB_LINK += $(LLVM_LIBS)
 # Because this module includes C++ files, we need to use a C++
 # compiler for linking. Makefile.shlib uses $(COMPILER) to build
 # loadable modules.
-override COMPILER = $(CXX) $(CFLAGS)
+override COMPILER = $(CXX) $(CXXFLAGS)
 
 OBJS = \
        $(WIN32RES)