[Buildroot] [PATCH v2 1/1] package/yajl: Update patch to link with libm

[Jörg Krause]

Dear Bernd Kuhls,

On Di, 2016-04-19 at 19:13 +0200, Bernd Kuhls wrote:
> Currently yajl does not compile using gcc6 from
> http://patchwork.ozlabs.org/patch/611249/
> 
> Patch 0003 needed a rebase after patch 0001 was replaced by a version
> which also works with gcc6.
> 
> This patch also fixes current build failures:
> http://autobuild.buildroot.net/results/05b/05b1847bc838a328e7398d03a4
> bb0efb95ef3938/
> 
> Signed-off-by: Bernd Kuhls <bernd.kuhls at t-online.de>
> ---
> v2: updated patch description, patch is needed not only for gcc6
> 
>  ...1-cmake-uClibc-Fix-missing-libm-for-tests.patch | 30 ------------
> -------
>  .../yajl/0001-cmake-uClibc-Fix-missing-libm.patch  | 34
> ++++++++++++++++++++++
>  ...ink-with-shared-libyajl-in-a-shared-build.patch |  6 ++--
>  3 files changed, 37 insertions(+), 33 deletions(-)
>  delete mode 100644 package/yajl/0001-cmake-uClibc-Fix-missing-libm-
> for-tests.patch
>  create mode 100644 package/yajl/0001-cmake-uClibc-Fix-missing-
> libm.patch
> 
> diff --git a/package/yajl/0001-cmake-uClibc-Fix-missing-libm-for-
> tests.patch b/package/yajl/0001-cmake-uClibc-Fix-missing-libm-for-
> tests.patch
> deleted file mode 100644
> index 08553f9..0000000
> --- a/package/yajl/0001-cmake-uClibc-Fix-missing-libm-for-tests.patch
> +++ /dev/null
> @@ -1,30 +0,0 @@
> -From a36814a6f9fbb62f49897f9fb1e68d204602e199 Mon Sep 17 00:00:00
> 2001
> -From: Maxime Hadjinlian <maxime.hadjinlian at gmail.com>
> -Date: Tue, 2 Feb 2016 17:28:31 +0100
> -Subject: [PATCH] cmake: uClibc: Fix missing libm for tests
> -
> -At the link time, the tests are not linked against libm which cause
> an
> -error with uClibc based toolchain:
> -
> -../../yajl-2.1.0/lib/libyajl.so.2.1.0: undefined reference to
> `__isnan'
> -../../yajl-2.1.0/lib/libyajl.so.2.1.0: undefined reference to
> `__isinf'
> -
> -Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian at gmail.com>
> ----
> - test/api/CMakeLists.txt | 2 +-
> - 1 file changed, 1 insertion(+), 1 deletion(-)
> -
> -diff --git a/test/api/CMakeLists.txt b/test/api/CMakeLists.txt
> -index cd65a54..e0ce2f6 100644
> ---- a/test/api/CMakeLists.txt
> -+++ b/test/api/CMakeLists.txt
> -@@ -21,5 +21,5 @@
> LINK_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR}/../../${YAJL_DIST_NAME}/
> lib)
> - FOREACH (test ${TESTS})
> -   GET_FILENAME_COMPONENT(testProg ${test} NAME_WE)
> -   ADD_EXECUTABLE(${testProg} ${test})
> --  TARGET_LINK_LIBRARIES(${testProg} yajl)
> -+  TARGET_LINK_LIBRARIES(${testProg} yajl m)
> - ENDFOREACH()
> --- 
> -2.7.0
> -
> diff --git a/package/yajl/0001-cmake-uClibc-Fix-missing-libm.patch
> b/package/yajl/0001-cmake-uClibc-Fix-missing-libm.patch
> new file mode 100644
> index 0000000..3564cb2
> --- /dev/null
> +++ b/package/yajl/0001-cmake-uClibc-Fix-missing-libm.patch
> @@ -0,0 +1,34 @@
> +From 76f6ead65b46e4a9cceca4e21efa940cc8a77a6e Mon Sep 17 00:00:00
> 2001
> +From: Bernd Kuhls <bernd.kuhls at t-online.de>
> +Date: Sat, 16 Apr 2016 19:28:41 +0200
> +Subject: [PATCH 1/1] cmake: uClibc: Fix missing libm
> +MIME-Version: 1.0
> +Content-Type: text/plain; charset=UTF-8
> +Content-Transfer-Encoding: 8bit
> +
> +Patch created by René Rhéaume, downloaded from
> +https://bugs.gentoo.org/show_bug.cgi?id=512738#c9
> +
> +Patch is discussed upstream:
> +https://github.com/lloyd/yajl/pull/184#issuecomment-201549734
> +
> +Signed-off-by: Bernd Kuhls <bernd.kuhls at t-online.de>
> +---
> + CMakeLists.txt | 1 +
> + 1 file changed, 1 insertion(+)
> +
> +diff --git a/CMakeLists.txt b/CMakeLists.txt
> +index 471eee1..08d69ec 100644
> +--- a/CMakeLists.txt
> ++++ b/CMakeLists.txt
> +@@ -60,6 +60,7 @@ ELSE (WIN32)
> + 
> +   SET(CMAKE_C_FLAGS_DEBUG "-DDEBUG -g")
> +   SET(CMAKE_C_FLAGS_RELEASE "-DNDEBUG -O2 -Wuninitialized")
> ++  SET(CMAKE_SHARED_LINKER_FLAGS "-lm ${CMAKE_SHARED_LINKER_FLAGS}")
> + ENDIF (WIN32)
> + 
> + 
> +-- 
> +2.8.0.rc3
> +
> diff --git a/package/yajl/0003-Link-with-shared-libyajl-in-a-shared-
> build.patch b/package/yajl/0003-Link-with-shared-libyajl-in-a-shared-
> build.patch
> index 6a6e5e3..46e652d 100644
> --- a/package/yajl/0003-Link-with-shared-libyajl-in-a-shared-
> build.patch
> +++ b/package/yajl/0003-Link-with-shared-libyajl-in-a-shared-
> build.patch
> @@ -82,11 +82,11 @@ index e0ce2f6..9adebdc 100644
>   FOREACH (test ${TESTS})
>     GET_FILENAME_COMPONENT(testProg ${test} NAME_WE)
>     ADD_EXECUTABLE(${testProg} ${test})
> --  TARGET_LINK_LIBRARIES(${testProg} yajl m)
> +-  TARGET_LINK_LIBRARIES(${testProg} yajl)
>  +  IF(BUILD_SHARED_LIBS)
> -+    TARGET_LINK_LIBRARIES(${testProg} yajl m)
> ++    TARGET_LINK_LIBRARIES(${testProg} yajl)
>  +  ELSE()
> -+    TARGET_LINK_LIBRARIES(${testProg} yajl_s m)
> ++    TARGET_LINK_LIBRARIES(${testProg} yajl_s)
>  +  ENDIF()
>   ENDFOREACH()
>  diff --git a/test/parsing/CMakeLists.txt
> b/test/parsing/CMakeLists.txt

While this patch indeed fixes the build issue for shared builds, it
does not for static builds.

In my opinion the macro CMAKE_SHARED_LINKER_FLAGS is not the right
place to add the library. I would prefer to use TARGET_LINK_LIBRARIES.
Of course, it's tedious to add '-lm' to each CMakeLists.txt, so a macro
YAJL_LIBS should be defined and used instead.

Furthermore, linking with libmath is not required with every C library,
so the need for '-lm' could (should?) be detected and added to
YAJL_LIBS conditionally.

Best regards
Jörg Krause