From e096ea9ac354ef50211d1298929d55caad8a7a58 Mon Sep 17 00:00:00 2001
From: Ciaran McCreesh <c.mccreesh.1@research.gla.ac.uk>
Date: Thu, 19 Dec 2013 15:58:27 +0000
Subject: [PATCH] Add TGT_CC and TGT_CXX

When building a project, some of which uses MPI, CC and CXX may need to
be overridden. We don't really want to use the MPI compiler for
everything, though, so being able to selectively specify a compiler is
helpful.
---
 MANUAL   | 10 ++++++++++
 Makefile |  6 ++++++
 2 files changed, 16 insertions(+)

diff --git a/MANUAL b/MANUAL
index 1c7ffe7..0f30666 100644
--- a/MANUAL
+++ b/MANUAL
@@ -147,11 +147,21 @@ TARGET_DIR
 
    Default value: . (make's working directory; aka project root)
 
+TGT_CC
+------
+   Specifies the program to be used for compiling C sources. If this option is
+    not specified, CC is used.
+
 TGT_CFLAGS
 ----------
    Like SRC_CFLAGS, but applies to all sources belonging to the current target,
    not just sources in the current submakefile.
 
+TGT_CXX
+-------
+   Specifies the program to be used for compiling C++ sources. If this option
+    is not specified, CXX is used.
+
 TGT_CXXFLAGS
 ------------
    Like SRC_CXXFLAGS, but applies to all sources belonging to the current
diff --git a/Makefile b/Makefile
index 8375cfc..3fd0f15 100644
--- a/Makefile
+++ b/Makefile
@@ -139,7 +139,9 @@ define INCLUDE_SUBMAKEFILE
     # Initialize all variables that can be defined by a makefile fragment, then
     # include the specified makefile fragment.
     TARGET        :=
+    TGT_CC        :=
     TGT_CFLAGS    :=
+    TGT_CXX       :=
     TGT_CXXFLAGS  :=
     TGT_DEFS      :=
     TGT_INCDIRS   :=
@@ -185,7 +187,9 @@ define INCLUDE_SUBMAKEFILE
         # makefile apply to this new target. Initialize the target's variables.
         TGT := $$(strip $${TARGET})
         ALL_TGTS += $${TGT}
+        $${TGT}_CC        := $${TGT_CC}
         $${TGT}_CFLAGS    := $${TGT_CFLAGS}
+        $${TGT}_CXX       := $${TGT_CXX}
         $${TGT}_CXXFLAGS  := $${TGT_CXXFLAGS}
         $${TGT}_DEFS      := $${TGT_DEFS}
         $${TGT}_DEPS      :=
@@ -247,6 +251,8 @@ define INCLUDE_SUBMAKEFILE
         # variables that were defined.
         $${TGT}_OBJS += $${OBJS}
         $${TGT}_DEPS += $${OBJS:%.o=%.P}
+        $${OBJS}: CC           := $$(if $${$${TGT}_CC},$${$${TGT}_CC},$${CC})
+        $${OBJS}: CXX          := $$(if $${$${TGT}_CXX},$${$${TGT}_CXX},$${CXX})
         $${OBJS}: SRC_CFLAGS   := $${$${TGT}_CFLAGS} $${SRC_CFLAGS}
         $${OBJS}: SRC_CXXFLAGS := $${$${TGT}_CXXFLAGS} $${SRC_CXXFLAGS}
         $${OBJS}: SRC_DEFS     := $$(addprefix -D,$${$${TGT}_DEFS} $${SRC_DEFS})