Respect the CC and CXX environment variables when cross building.

build.sh

@@ -20,6 +20,8 @@ flags=(-DCMAKE_BUILD_PO=FALSE)
 
 cleanBuild=0
 useClang=0
+# 0 => no, 1 => yes, 2 => force yes
+useCross=0
 
 for ARG in "$@"; do
     case "$ARG" in
@@ -38,7 +40,7 @@ for ARG in "$@"; do
         --wx28        ) flags+=(-DWX28_API=TRUE) ;;
         --gtk3        ) flags+=(-DGTK3_API=TRUE) ;;
         --no-simd     ) flags+=(-DDISABLE_ADVANCE_SIMD=TRUE) ;;
-        --cross-multilib ) flags+=(-DCMAKE_TOOLCHAIN_FILE=cmake/linux-compiler-i386-multilib.cmake) ;;
+        --cross-multilib ) flags+=(-DCMAKE_TOOLCHAIN_FILE=cmake/linux-compiler-i386-multilib.cmake); useCross=1; ;;
         -D*           ) flags+=($ARG) ;;
 
         *)
@@ -92,7 +94,11 @@ mkdir -p $build
 cd $build
 
 if [[ "$useClang" -eq 1 ]]; then
+    if [[ "$useCross" -eq 0 ]]; then
         CC=clang CXX=clang++ cmake "${flags[@]}" $root 2>&1 | tee -a $log
+    else
+        CC="clang -m32" CXX="clang++ -m32" cmake "${flags[@]}" $root 2>&1 | tee -a $log
+    fi
 else
     cmake "${flags[@]}" $root 2>&1 | tee -a $log
 fi

cmake/BuildParameters.cmake

@@ -64,6 +64,7 @@ option(USE_ASAN "Enable address sanitizer")
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
     set(USE_CLANG TRUE)
+    message(STATUS "Building with Clang/LLVM.")
 endif()
 
 #-------------------------------------------------------------------------------

cmake/darwin-compiler-i386-generic.cmake

@@ -3,8 +3,10 @@ set(CMAKE_SYSTEM_NAME Darwin)
 set(CMAKE_SYSTEM_PROCESSOR i686)
 
 # Leave it generic since it could be clang, gnu, etc.
+if("$ENV{CC}" STREQUAL "" OR "$ENV{CXX}" STREQUAL "")
     set(CMAKE_C_COMPILER cc -m32)
     set(CMAKE_CXX_COMPILER c++ -m32)
+endif()
 
 # If given a CMAKE_FIND_ROOT_PATH then
 # FIND_PROGRAM ignores CMAKE_FIND_ROOT_PATH (probably can't run)

cmake/linux-compiler-i386-multilib.cmake

@@ -4,8 +4,10 @@ set(CMAKE_SYSTEM_PROCESSOR i686)
 
 # It could be i?86-*linux-gnu, x86_64-*linux-gnu, x86_64-*linux-gnux32, etc.
 # Leave it generic to only support amd64 or x32 to i386 with any compiler.
+if("$ENV{CC}" STREQUAL "" OR "$ENV{CXX}" STREQUAL "")
     set(CMAKE_C_COMPILER cc -m32)
     set(CMAKE_CXX_COMPILER c++ -m32)
+endif()
 
 # cmake 2.8.5 correctly sets CMAKE_LIBRARY_ARCHITECTURE for Debian multiarch.
 # Be really strict about what gets used.