(jm_MACROS): Add a test to see if -lm is required

to link seq.  If so, set SEQ_LIBM to -lm.  From Bruno Haible.

diff --git a/m4/jm-macros.m4 b/m4/jm-macros.m4
index 6ed662cfd32c8f8d7eb1cc68a7d831bfb68a5a55..b60b6ff22784ad024161cbb10d4098406b845865 100644 (file)
--- a/m4/jm-macros.m4
+++ b/m4/jm-macros.m4
@@ -188,6 +188,22 @@ AC_DEFUN(jm_MACROS,
   AC_SUBST(POW_LIBM)
   test $am_cv_func_strtod_needs_libm = yes && POW_LIBM=-lm
 
+  # See if linking `seq' requires -lm.
+  # It does on nearly every system.  The single exception (so far) is
+  # BeOS which doesn't even have a separate math library.
+  AC_SUBST(SEQ_LIBM)
+  ac_seq_body='
+     static double x, y;
+     x = floor (x);
+     x = rint (x);
+     x = modf (x, &y);'
+  AC_TRY_LINK([#include <math.h>], $ac_seq_body, ,
+    [ac_seq_save_LIBS="$LIBS"
+     LIBS="$LIBS -lm"
+     AC_TRY_LINK([#include <math.h>], $ac_seq_body, SEQ_LIBM=-lm)
+     LIBS="$ac_seq_save_LIBS"
+    ])
+
   jm_LANGINFO_CODESET
   jm_GLIBC21
   jm_ICONV