ENH: add optional -clang flag for building gcc

- can be useful when bootstrapping

etc/tools/ThirdPartyFunctions

@@ -64,7 +64,7 @@ exportLinker()
 # Force use of gcc/g++
 useGcc()
 {
-    export CC=gcc    # Use gcc/g++
+    export CC=gcc
     export CXX=g++
 }
 

makeADIOS

@@ -41,8 +41,8 @@ usage() {
 
 usage: ${0##*/} [OPTION] [adios-VERSION] [-- configure-options]
 options:
-  -cmake PATH       With cmake from the path given
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -cmake PATH   With cmake from the path given
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * Build ADIOS

makeADIOS2

@@ -39,8 +39,8 @@ usage() {
 
 usage: ${0##*/} [OPTION] [adios-VERSION]
 options:
-  -cmake PATH       With cmake from the path given
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -cmake PATH   With cmake from the path given
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * Build ADIOS2

makeCCMIO

@@ -51,7 +51,7 @@ usage()
 
 Usage: ${0##*/} [OPTION] [lib|libso] [libccmio-VERSION]
 options:
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * Compile the proprietary libccmio library

makeCmake

@@ -42,8 +42,8 @@ usage() {
 
 usage: ${0##*/} [OPTION] cmake-VERSION
 options:
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
-  -link             Create additional symlink as 'cmake-system'
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
+  -link         Create additional symlink as 'cmake-system'
   -help
 
 * build cmake

makeFFTW

@@ -59,7 +59,7 @@ usage() {
 
 usage: ${0##*/} [OPTION] [fftw-VERSION] [-- configure-options]
 options:
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * build FFTW with

makeGcc

@@ -60,6 +60,7 @@ usage() {
 
 usage: ${0##*/} [OPTION] [gcc-VERSION] [gmp-VERSION] [mpfr-VERSION] [mpc-VERSION]
 options:
+  -clang            Force clang/clang++ for building
   -multilib         for 64-bit systems with 32-bit support required
   -no-multilib      for 64-bit systems without 32-bit support (DEFAULT)
   -no-threadsafe    disable mpfr thread-safe (default is auto-detect)
@@ -86,6 +87,10 @@ do
     case "$1" in
     '') ;;      # Ignore empty
     -h | -help) usage   ;;
+    -clang)     # Force use of clang/clang++ for building
+        export CC=clang
+        export CXX=clang++
+        ;;
 
     -multi*)
         optMultilib=enable
@@ -133,6 +138,8 @@ GCC configuration
     MPFR    = $mpfrPACKAGE
     MPC     = $mpcPACKAGE
 ------------------
+Using CC    = $CC $CFLAGS
+Using CXX   = $CXX $CXXFLAGS
 SUMMARY
 
 # Set 32 or 64 bit ABI

makeGperftools

@@ -41,7 +41,7 @@ usage() {
 
 usage: ${0##*/} [gperftools-VERSION]
 options:
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * build gperftools

makeKAHIP

@@ -75,7 +75,7 @@ usage()
 
 Usage: ${0##*/} [OPTION] [lib|libso] [kahip-VERSION]
 options:
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * Compile KaHIP

makeMETIS

@@ -74,7 +74,7 @@ usage() {
 
 usage: ${0##*/} [OPTION] [lib|libso] [METIS-VERSION]
 options:
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * build METIS with

makeMGridGen

@@ -42,7 +42,7 @@ usage() {
 
 usage: ${0##*/} [OPTION] [mgridgen-VERSION]
 options:
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * Build MGridGen

makeMesa

@@ -49,7 +49,7 @@ usage() {
 
 usage: ${0##*/} [OPTION] mesa-VERSION [-- configure-options]
 options:
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * build Mesa with

makeOPENMPI

@@ -70,7 +70,7 @@ usage() {
 
 usage: ${0##*/} [OPTION] [openmpi-VERSION] [-- configure-options]
 options:
-  -gcc          Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -gcc          Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -memcheck     Configure with --enable-memcheck (requires valgrind.h)
   -threaded     Configure with --enable-mpi-thread-multiple
   -no-threaded  Configure with --disable-mpi-thread-multiple

makeQt

@@ -35,7 +35,7 @@ usage() {
 
 usage: ${0##*/} [OPTION] [qt-VERSION] [-- configure-options]
 options:
-  -gcc              Force gcc/g++ instead of the values from \$WM_CC, \$WM_CXX
+  -gcc              Force gcc/g++ instead of using \$WM_CC, \$WM_CXX
   -help
 
 * build $qtTYPE, version ${qtVERSION:-undefined}