package/json-c/0002-Link-against-libm-when-needed.patch

   1 From ccb15ee3d7e8c925cb3af9ea805feea2863c4f81 Mon Sep 17 00:00:00 2001
   2 From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   3 Date: Fri, 1 May 2015 12:52:18 +0200
   4 Subject: [PATCH] Link against libm when needed
   5
   6 In certain C libraries (e.g uClibc), isnan() and related functions are
   7 implemented in libm, so json-c needs to link against it. This commit
   8 therefore adds an AC_TRY_LINK() test to check whether a program
   9 calling isnan() can be properly linked with no special flags. If not,
  10 we assume linking against libm is needed.
  11
  12 The json-c.pc.in file is also adjusted so that in the case of static
  13 linking against json-c, -lm is also used.
  14
  15 Submitted upstream: https://github.com/json-c/json-c/pull/182
  16
  17 Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
  18 ---
  19  configure.ac | 4 ++++
  20  json-c.pc.in | 3 ++-
  21  2 files changed, 6 insertions(+), 1 deletion(-)
  22
  23 diff --git a/configure.ac b/configure.ac
  24 index 99660a4..2a14ccf 100644
  25 --- a/configure.ac
  26 +++ b/configure.ac
  27 @@ -50,6 +50,10 @@ AC_CHECK_DECLS([isinf], [], [], [[#include <math.h>]])
  28  AC_CHECK_DECLS([_isnan], [], [], [[#include <float.h>]])
  29  AC_CHECK_DECLS([_finite], [], [], [[#include <float.h>]])
  30
  31 +if test "$ac_cv_have_decl_isnan" = "yes" ; then
  32 +   AC_TRY_LINK([#include <math.h>], [float f = 0.0; return isnan(f)], [], [LIBS="$LIBS -lm"])
  33 +fi
  34 +
  35  #check if .section.gnu.warning accepts long strings (for __warn_references)
  36  AC_LANG_PUSH([C])
  37
  38 diff --git a/json-c.pc.in b/json-c.pc.in
  39 index 037739d..05bfbc8 100644
  40 --- a/json-c.pc.in
  41 +++ b/json-c.pc.in
  42 @@ -6,6 +6,7 @@ includedir=@includedir@
  43  Name: json-c
  44  Description: JSON implementation in C
  45  Version: @VERSION@
  46 -Requires:
  47 +Requires:
  48 +Libs.private: @LIBS@
  49  Libs:  -L${libdir} -ljson-c
  50  Cflags: -I${includedir}/json-c
  51 --
  52 2.1.0
  53