CMake build system

cmake/utils/find_include_dirs.cmake

@@ -0,0 +1,37 @@
+include_guard(GLOBAL)
+
+function(find_include_dirs OUT_VAR)
+    set(SOURCES ${ARGN})
+
+    # Get top most common directory prefix for all source files
+    set(COMMON_PATH "")
+    foreach(FILE IN LISTS SOURCES)
+        get_filename_component(DIR ${FILE} DIRECTORY)
+        file(REAL_PATH ${DIR} DIR)
+        if(COMMON_PATH STREQUAL "")
+            set(COMMON_PATH ${DIR})
+        else()
+            string(LENGTH ${COMMON_PATH} PREFIX_LEN)
+            while(NOT ${DIR} MATCHES "^${COMMON_PATH}(/|$)" AND PREFIX_LEN GREATER 0)
+                string(SUBSTRING ${COMMON_PATH} 0 ${PREFIX_LEN} COMMON_PATH)
+                math(EXPR PREFIX_LEN "${PREFIX_LEN} - 1")
+            endwhile()
+        endif()
+    endforeach()
+
+    if(NOT IS_DIRECTORY ${COMMON_PATH})
+        message(FATAL_ERROR "Could not determine common directory for source files")
+    endif()
+
+    # Recursively find directories that contain .h files under common directory
+    file(GLOB_RECURSE HEADER_FILES ${COMMON_PATH}/*.h)
+    set(INCLUDE_DIRS "")
+    foreach(HEADER_FILE IN LISTS HEADER_FILES)
+        get_filename_component(HEADER_DIR ${HEADER_FILE} DIRECTORY)
+        list(APPEND INCLUDE_DIRS ${HEADER_DIR})
+    endforeach()
+
+    list(REMOVE_DUPLICATES INCLUDE_DIRS)
+
+    set(${OUT_VAR} ${INCLUDE_DIRS} PARENT_SCOPE)
+endfunction()