package/ola/0002-Remove-replacing-I-with-isystem.patch

   1 From bbb03794def326c2e8ad2de523c5a61a4c8cb464 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?J=C3=B6rg=20Krause?= <joerg.krause@embedded.rocks>
   3 Date: Thu, 22 Sep 2016 00:58:58 +0200
   4 Subject: [PATCH] Remove replacing -I with -isystem
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Building OLA with a GCC 6 cross-toolchain fails:
  10
  11 ```
  12 /usr/bin/arm-linux-g++ -DHAVE_CONFIG_H -I.   -D_LARGEFILE_SOURCE
  13 -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -I./include -I./include
  14 -Wall -Wformat -W -isystem
  15 /usr/arm-buildroot-linux-gnueabihf/sysroot/usr/include -pthread
  16 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os
  17 -pthread -c -o libs/acn/e131_transmit_test.o
  18 libs/acn/e131_transmit_test.cpp
  19 /usr/bin/arm-linux-g++ -DHAVE_CONFIG_H -I.   -D_LARGEFILE_SOURCE
  20 -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -I./include -I./include
  21 -Wall -Wformat -W -isystem
  22 /usr/arm-buildroot-linux-gnueabihf/sysroot/usr/include -pthread
  23 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os
  24 -pthread -c -o libs/acn/E131TestFramework.o
  25 libs/acn/E131TestFramework.cpp
  26 In file included from
  27 /opt/ext-toolchain/arm-buildroot-linux-gnueabihf/include/c++/6.1.0/ext/string_conversions.h:41:0,
  28                  from
  29 /opt/ext-toolchain/arm-buildroot-linux-gnueabihf/include/c++/6.1.0/bits/basic_string.h:5402,
  30                  from
  31 /opt/ext-toolchain/arm-buildroot-linux-gnueabihf/include/c++/6.1.0/string:52,
  32                  from ./tools/ola_trigger/config.ypp:2:
  33 /opt/ext-toolchain/arm-buildroot-linux-gnueabihf/include/c++/6.1.0/cstdlib:75:25:
  34 fatal error: stdlib.h: No such file or directory
  35  #include_next <stdlib.h>
  36                          ^
  37 compilation terminated.
  38 ```
  39
  40 The C++ library in GCC 6 now provides its own `<stdlib.h>` header that
  41 wraps the C library header of the same name, so in `<cstdlib>` the
  42 header include
  43
  44 ```
  45 #include <stdlib.h>
  46 ```
  47
  48 has become
  49
  50 ```
  51 #include_next <stdlib.h>
  52 ```
  53
  54 `#include_next` is sensitive to the order of directories in the
  55 preprocessor's search path, so if that order is changed with `-isystem`
  56 then the compiler can't find the right header:
  57
  58 ```
  59 [1] /usr/arm-buildroot-linux-gnueabihf/sysroot/usr/include
  60 [2] /opt/ext-toolchain/arm-buildroot-linux-gnueabihf/include/c++/6.1.0
  61 [..]
  62 End of search list.
  63 ```
  64
  65 `<cstdlib>` is located in [2] whereas `<stdlib.h>` (C library header) is
  66 in [1]. In this case, the `#include_next <stdlib.h>` statement in
  67 `<cstdlib>`, located in [2], is evaluated **after** the search path [1],
  68 so the compiler does not find the right system header.
  69
  70 The problem is that the OLA build system replaces the `-I` in the CFLAGS
  71 from libprotobuf with `-isystem` to fix some warnings treated as errors
  72 in the libprotobuf header files.
  73
  74 `-isystem` should be used to suppress warnings in system headers only
  75 and the libprotobuf header files are not system files.
  76
  77 The correct fix is to compile with less restrictions and remove
  78 `-Werror` for the build.
  79
  80 As using `-isystem` is reordering GCCs search path and using `-isystem`
  81 is really not necessary, remove the faulty replacement of `-I`.
  82
  83 Upstream status: https://github.com/OpenLightingProject/ola/pull/1126
  84
  85 Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
  86 ---
  87  config/ola.m4 | 3 ---
  88  1 file changed, 3 deletions(-)
  89
  90 diff --git a/config/ola.m4 b/config/ola.m4
  91 index 2796cfb..d3b8cc8 100644
  92 --- a/config/ola.m4
  93 +++ b/config/ola.m4
  94 @@ -24,9 +24,6 @@ AC_DEFUN([PROTOBUF_SUPPORT],
  95  AC_REQUIRE_CPP()
  96  PKG_CHECK_MODULES(libprotobuf, [protobuf >= $1])
  97
  98 -# We want to replace -I with -isystem here to disable errors in the .h files
  99 -# See https://groups.google.com/forum/#!topic/open-lighting/39Mj0KXlCIk
 100 -libprotobuf_CFLAGS=`echo $libprotobuf_CFLAGS | sed 's/-I/-isystem /'`
 101  AC_SUBST([libprotobuf_CFLAGS])
 102
 103  AC_ARG_WITH([protoc],
 104 --
 105 2.10.0
 106