cmake: revert "add option to disable -isystem"

src/cmake-1-fixes.patch

@@ -5,7 +5,7 @@ Contains ad hoc patches for cross building.
 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
 From: Tony Theodore <tonyt@logyst.com>
 Date: Fri, 12 Aug 2016 02:01:20 +1000
-Subject: [PATCH 1/3] fix windres invocation options
+Subject: [PATCH 1/2] fix windres invocation options
 
 windres doesn't recognise various gcc flags like -mms-bitfields,
 -fopenmp, -mthreads etc. (basically not `-D` or `-I`)
@@ -18,43 +18,17 @@ index 1111111..2222222 100644
 -set(CMAKE_RC_COMPILE_OBJECT "<CMAKE_RC_COMPILER> -O coff <DEFINES> <INCLUDES> <FLAGS> <SOURCE> <OBJECT>")
 +set(CMAKE_RC_COMPILE_OBJECT "<CMAKE_RC_COMPILER> -O coff <DEFINES> <INCLUDES> <SOURCE> <OBJECT>")
 
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Tony Theodore <tonyt@logyst.com>
-Date: Tue, 25 Jul 2017 20:34:56 +1000
-Subject: [PATCH 2/3] add option to disable -isystem
-
-taken from (not accepted):
-https://gitlab.kitware.com/cmake/cmake/merge_requests/895
-
-see also:
-https://gitlab.kitware.com/cmake/cmake/issues/16291
-https://gitlab.kitware.com/cmake/cmake/issues/16919
-
-diff --git a/Modules/Compiler/GNU.cmake b/Modules/Compiler/GNU.cmake
-index 1111111..2222222 100644
---- a/Modules/Compiler/GNU.cmake
-+++ b/Modules/Compiler/GNU.cmake
-@@ -42,7 +42,7 @@ macro(__compiler_gnu lang)
-   string(APPEND CMAKE_${lang}_FLAGS_RELWITHDEBINFO_INIT " -O2 -g -DNDEBUG")
-   set(CMAKE_${lang}_CREATE_PREPROCESSED_SOURCE "<CMAKE_${lang}_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> > <PREPROCESSED_SOURCE>")
-   set(CMAKE_${lang}_CREATE_ASSEMBLY_SOURCE "<CMAKE_${lang}_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -S <SOURCE> -o <ASSEMBLY_SOURCE>")
--  if(NOT APPLE OR NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 4) # work around #4462
-+  if(NOT APPLE OR NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 4 AND (NOT MXE_DISABLE_INCLUDE_SYSTEM_FLAG)) # work around #4462
-     set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang} "-isystem ")
-   endif()
- endmacro()
-
 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
 From: Tony Theodore <tonyt@logyst.com>
 Date: Tue, 15 Aug 2017 15:25:06 +1000
-Subject: [PATCH 3/3] add CPACK_NSIS_EXECUTABLE variable
+Subject: [PATCH 2/2] add CPACK_NSIS_EXECUTABLE variable
 
 
 diff --git a/Source/CPack/cmCPackNSISGenerator.cxx b/Source/CPack/cmCPackNSISGenerator.cxx
 index 1111111..2222222 100644
 --- a/Source/CPack/cmCPackNSISGenerator.cxx
 +++ b/Source/CPack/cmCPackNSISGenerator.cxx
-@@ -384,7 +384,9 @@ int cmCPackNSISGenerator::InitializeInternal()
+@@ -374,7 +374,9 @@ int cmCPackNSISGenerator::InitializeInternal()
    }
  #endif