allow configuring android project path in android_ndk_gdb_enable()

AndroidNdkGdb.cmake

@@ -41,21 +41,30 @@
 
 # add gdbserver and general gdb configuration to project
 # also create a mininal NDK skeleton so ndk-gdb finds the paths
+#
+# the optional parameter defines the path to the android project.
+# uses PROJECT_SOURCE_DIR by default.
 macro(android_ndk_gdb_enable)
     if(ANDROID)
         # create custom target that depends on the real target so it gets executed afterwards
         add_custom_target(NDK_GDB ALL)
 
-        set(NDK_GDB_SOLIB_PATH ${PROJECT_SOURCE_DIR}/obj/local/${ANDROID_NDK_ABI_NAME}/)
+        if(${ARGC})
+            set(ANDROID_PROJECT_DIR ${ARGV0})
+        else()
+            set(ANDROID_PROJECT_DIR ${PROJECT_SOURCE_DIR})
+        endif()
+
+        set(NDK_GDB_SOLIB_PATH ${ANDROID_PROJECT_DIR}/obj/local/${ANDROID_NDK_ABI_NAME}/)
         file(MAKE_DIRECTORY ${NDK_GDB_SOLIB_PATH})
 
         # 1. generate essential Android Makefiles
-        file(MAKE_DIRECTORY ${PROJECT_SOURCE_DIR}/jni)
-        if(NOT EXISTS ${PROJECT_SOURCE_DIR}/jni/Android.mk)
-            file(WRITE ${PROJECT_SOURCE_DIR}/jni/Android.mk "APP_ABI := ${ANDROID_NDK_ABI_NAME}\n")
+        file(MAKE_DIRECTORY ${ANDROID_PROJECT_DIR}/jni)
+        if(NOT EXISTS ${ANDROID_PROJECT_DIR}/jni/Android.mk)
+            file(WRITE ${ANDROID_PROJECT_DIR}/jni/Android.mk "APP_ABI := ${ANDROID_NDK_ABI_NAME}\n")
         endif()
-        if(NOT EXISTS ${PROJECT_SOURCE_DIR}/jni/Application.mk)
-            file(WRITE ${PROJECT_SOURCE_DIR}/jni/Application.mk "APP_ABI := ${ANDROID_NDK_ABI_NAME}\n")
+        if(NOT EXISTS ${ANDROID_PROJECT_DIR}/jni/Application.mk)
+            file(WRITE ${ANDROID_PROJECT_DIR}/jni/Application.mk "APP_ABI := ${ANDROID_NDK_ABI_NAME}\n")
         endif()
 
         # 2. generate gdb.setup