From ccb15ee3d7e8c925cb3af9ea805feea2863c4f81 Mon Sep 17 00:00:00 2001 From: Thomas Petazzoni Date: Fri, 1 May 2015 12:52:18 +0200 Subject: [PATCH] Link against libm when needed In certain C libraries (e.g uClibc), isnan() and related functions are implemented in libm, so json-c needs to link against it. This commit therefore adds an AC_TRY_LINK() test to check whether a program calling isnan() can be properly linked with no special flags. If not, we assume linking against libm is needed. The json-c.pc.in file is also adjusted so that in the case of static linking against json-c, -lm is also used. Submitted upstream: https://github.com/json-c/json-c/pull/182 Signed-off-by: Thomas Petazzoni --- configure.ac | 4 ++++ json-c.pc.in | 3 ++- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/configure.ac b/configure.ac index 99660a4..2a14ccf 100644 --- a/configure.ac +++ b/configure.ac @@ -50,6 +50,10 @@ AC_CHECK_DECLS([isinf], [], [], [[#include ]]) AC_CHECK_DECLS([_isnan], [], [], [[#include ]]) AC_CHECK_DECLS([_finite], [], [], [[#include ]]) +if test "$ac_cv_have_decl_isnan" = "yes" ; then + AC_TRY_LINK([#include ], [float f = 0.0; return isnan(f)], [], [LIBS="$LIBS -lm"]) +fi + #check if .section.gnu.warning accepts long strings (for __warn_references) AC_LANG_PUSH([C]) diff --git a/json-c.pc.in b/json-c.pc.in index 037739d..05bfbc8 100644 --- a/json-c.pc.in +++ b/json-c.pc.in @@ -6,6 +6,7 @@ includedir=@includedir@ Name: json-c Description: JSON implementation in C Version: @VERSION@ -Requires: +Requires: +Libs.private: @LIBS@ Libs: -L${libdir} -ljson-c Cflags: -I${includedir}/json-c -- 2.1.0