feat(cmakev2/idf): enable ccache if requested

Enable ccache if CCACHE_ENABLE is set.

Signed-off-by: Frantisek Hrbata <frantisek.hrbata@espressif.com>

tools/cmakev2/idf.cmake

@@ -316,6 +316,25 @@ function(__init_toolchain)
     idf_build_set_property(IDF_TOOLCHAIN_FILE "${toolchain_file}")
 endfunction()
 
+#[[
+   __init_ccache()
+
+   Enable ccache if requested through CCACHE_ENABLE.
+#]]
+function(__init_ccache)
+    if(NOT CCACHE_ENABLE)
+        return()
+    endif()
+
+    find_program(CCACHE_FOUND ccache)
+    if(CCACHE_FOUND)
+        idf_msg("ccache will be used for faster recompilation")
+        set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ccache)
+    else()
+        idf_warn("enabled ccache in build but ccache program not found")
+    endif()
+endfunction()
+
 #[[
    __init_components()
 
@@ -565,6 +584,9 @@ __init_idf_target()
 # Set IDF_TOOLCHAIN, IDF_TOOLCHAIN_FILE and CMAKE_TOOLCHAIN_FILE.
 __init_toolchain()
 
+# Enable ccache if requested.
+__init_ccache()
+
 # Discover and initialize components.
 __init_components()