Enhance ICU build configuration to use ccache as a compiler wrapper for improved performance

Author: royshil

cmake/BuildICU.cmake

@@ -52,8 +52,9 @@ else()
   find_program(CCACHE_PROGRAM ccache)
   if(CCACHE_PROGRAM)
     message(STATUS "Found ccache: ${CCACHE_PROGRAM}")
-    set(CMAKE_C_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")
-    set(CMAKE_CXX_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")
+    # Create compiler wrapper commands
+    set(C_LAUNCHER "${CCACHE_PROGRAM} ${CMAKE_C_COMPILER}")
+    set(CXX_LAUNCHER "${CCACHE_PROGRAM} ${CMAKE_CXX_COMPILER}")
   endif()
 
   set(ICU_URL
@@ -63,20 +64,11 @@ else()
   if(APPLE)
     set(ICU_PLATFORM "MacOSX")
     set(TARGET_ARCH -arch\ $ENV{MACOS_ARCH})
-    set(ICU_BUILD_ENV_VARS
-        CFLAGS=${TARGET_ARCH}
-        CXXFLAGS=${TARGET_ARCH}
-        LDFLAGS=${TARGET_ARCH}
-        CC="${CMAKE_C_COMPILER_LAUNCHER} ${CMAKE_C_COMPILER}"
-        CXX="${CMAKE_CXX_COMPILER_LAUNCHER} ${CMAKE_CXX_COMPILER}")
+    set(ICU_BUILD_ENV_VARS CFLAGS=${TARGET_ARCH} CXXFLAGS=${TARGET_ARCH} LDFLAGS=${TARGET_ARCH} CC=${C_LAUNCHER}
+                           CXX=${CXX_LAUNCHER})
   else()
     set(ICU_PLATFORM "Linux")
-    set(ICU_BUILD_ENV_VARS
-        CFLAGS=-fPIC
-        CXXFLAGS=-fPIC
-        LDFLAGS=-fPIC
-        CC="${CMAKE_C_COMPILER_LAUNCHER} ${CMAKE_C_COMPILER}"
-        CXX="${CMAKE_CXX_COMPILER_LAUNCHER} ${CMAKE_CXX_COMPILER}")
+    set(ICU_BUILD_ENV_VARS CFLAGS=-fPIC CXXFLAGS=-fPIC LDFLAGS=-fPIC CC=${C_LAUNCHER} CXX=${CXX_LAUNCHER})
   endif()
 
   ExternalProject_Add(