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 5cffac90aa5fbccd7e5879675e257f51724c973e..1af95582ea35cae4bb8ccb650e137b1f7d6d4552 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)