From 643e6064bb233e5ff9c286831d98b5e29ad696c0 Mon Sep 17 00:00:00 2001
From: Yanfei Guo <yguo@anl.gov>
Date: Wed, 25 Sep 2024 10:01:22 -0500
Subject: [PATCH] mpl: pass MPL's CFLAGS back to MPICH

MPL exports additional CFLAGS as MPL_CFLAGS. Only the ones that added
by the MPL configure will be passed. The PAC_CONFIG_MPL macro will add
them to CFLAGS.
---
 confdb/aclocal_modules.m4 | 1 +
 src/mpl/configure.ac      | 4 ++++
 src/mpl/localdefs.in      | 1 +
 3 files changed, 6 insertions(+)

diff --git a/confdb/aclocal_modules.m4 b/confdb/aclocal_modules.m4
index 2c5294ad24d..76f3c3cacca 100644
--- a/confdb/aclocal_modules.m4
+++ b/confdb/aclocal_modules.m4
@@ -18,6 +18,7 @@ AC_DEFUN([PAC_CONFIG_MPL],[
         PAC_CONFIG_MPL_EMBEDDED
         PAC_APPEND_FLAG([-I${main_top_builddir}/src/mpl/include], [CPPFLAGS])
         PAC_APPEND_FLAG([-I${use_top_srcdir}/src/mpl/include], [CPPFLAGS])
+        PAC_APPEND_FLAG([${MPL_CFLAGS}], [CFLAGS])
         mplsrcdir="src/mpl"
         mpllib="src/mpl/libmpl.la"
     ], [
diff --git a/src/mpl/configure.ac b/src/mpl/configure.ac
index 3986121fdeb..442bdd6131b 100644
--- a/src/mpl/configure.ac
+++ b/src/mpl/configure.ac
@@ -29,6 +29,7 @@ LT_PREREQ([2.2.6])
 PAC_PUSH_FLAG([CFLAGS])
 LT_INIT()
 PAC_POP_FLAG([CFLAGS])
+PARENT_CFLAGS=${CFLAGS}
 
 # ----------------------------------------------------------------------------
 # Set default library names if names haven't already been provided
@@ -1405,6 +1406,9 @@ AX_GCC_VAR_ATTRIBUTE(used)
 
 PAC_POP_ALL_FLAGS
 
+MPL_CFLAGS="${CFLAGS#${PARENT_CFLAGS}}"
+AC_SUBST(MPL_CFLAGS)
+
 dnl Final output
 AC_CONFIG_FILES([Makefile localdefs include/mpl_timer.h])
 AC_OUTPUT
diff --git a/src/mpl/localdefs.in b/src/mpl/localdefs.in
index aaa0146b21b..3fb7a169514 100644
--- a/src/mpl/localdefs.in
+++ b/src/mpl/localdefs.in
@@ -5,5 +5,6 @@
 
 GPU_SUPPORT="@GPU_SUPPORT@"
 CPPFLAGS="@CPPFLAGS@"
+MPL_CFLAGS="@MPL_CFLAGS@"
 WRAPPER_LIBS="$WRAPPER_LIBS @LDFLAGS@ @LIBS@"
 COMPILER_TLS="@COMPILER_TLS@"