BUG: Use proper signature for EXEC_PROGRAM to get return value of cmake -E remove. Also fixed spelling error in message, and made non-existing files not a fatal error so that the rest of the files are removed.

cmake_uninstall.cmake.in

@@ -6,16 +6,17 @@ FILE(READ "@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt" files)
 STRING(REGEX REPLACE "\n" ";" files "${files}")
 FOREACH(file ${files})
   MESSAGE(STATUS "Uninstalling \"${file}\"")
-  IF(NOT EXISTS "${file}")
-    MESSAGE(FATAL_ERROR "File \"${file}\" does not exists.")
-  ENDIF(NOT EXISTS "${file}")
-  EXEC_PROGRAM("@CMAKE_COMMAND@" ARGS "-E remove \"${file}\""
-    OUTPUT_VARIABLE rm_out
-    RETURN_VARIABLE rm_retval)
-  IF("${rm_retval}" GREATER 0)
-    MESSAGE(FATAL_ERROR "Problem when removing \"${file}\"")
-  ENDIF("${rm_retval}" GREATER 0)
+  IF(EXISTS "${file}")
+    EXEC_PROGRAM(
+      "@CMAKE_COMMAND@" ARGS "-E remove \"${file}\""
+      OUTPUT_VARIABLE rm_out
+      RETURN_VALUE rm_retval
+      )
+    IF("${rm_retval}" STREQUAL 0)
+    ELSE("${rm_retval}" STREQUAL 0)
+      MESSAGE(FATAL_ERROR "Problem when removing \"${file}\"")
+    ENDIF("${rm_retval}" STREQUAL 0)
+  ELSE(EXISTS "${file}")
+    MESSAGE(STATUS "File \"${file}\" does not exist.")
+  ENDIF(EXISTS "${file}")
 ENDFOREACH(file)
-
-
-