Get rid of PC_LIBM

It only existed to not include -lm in the .pc for fixed point builds,
but that is still needed since the float API is still enabled and
will use at least lrint.

configure.ac

@@ -125,7 +125,6 @@ AS_IF([test "$enable_fixed_point" = "yes"],[
 ],[
   enable_float="yes";
   PC_BUILD="floating-point"
-  PC_LIBM="$LIBM"
 ])
 
 AM_CONDITIONAL([FIXED_POINT], [test "$enable_fixed_point" = "yes"])
@@ -145,7 +144,6 @@ AC_ARG_ENABLE([custom-modes],
 AS_IF([test "$enable_custom_modes" = "yes"],[
   AC_DEFINE([CUSTOM_MODES], [1], [Custom modes])
   PC_BUILD="$PC_BUILD, custom modes"
-  PC_LIBM="$LIBM"
 ])
 
 AM_CONDITIONAL([CUSTOM_MODES], [test "$enable_custom_modes" = "yes"])
@@ -289,7 +287,6 @@ LIBS="$saved_LIBS"
 AC_CHECK_FUNCS([__malloc_hook])
 
 AC_SUBST([PC_BUILD])
-AC_SUBST([PC_LIBM])
 
 
 AC_CONFIG_FILES([Makefile opus.pc opus-uninstalled.pc

opus-uninstalled.pc.in

@@ -8,5 +8,5 @@ Description: Opus IETF audio codec (not installed, @PC_BUILD@)
 Version: @VERSION@
 Requires:
 Conflicts:
-Libs: ${libdir}/libopus.a @PC_LIBM@
+Libs: ${libdir}/libopus.a @LIBM@
 Cflags: -I${pcfiledir}/@top_srcdir@/include

opus.pc.in

@@ -12,5 +12,5 @@ Version: @VERSION@
 Requires:
 Conflicts:
 Libs: -L${libdir} -lopus
-Libs.private: @PC_LIBM@
+Libs.private: @LIBM@
 Cflags: -I${includedir}/opus