Add compat/fparseln() for non-BSD systems

Linux and friends don't natively have fparseln() so add it to compat/ and
ensure autotools can pick it up.

Makefile.am

@@ -213,6 +213,9 @@ endif
 if NO_FGETLN
 nodist_tmux_SOURCES += compat/fgetln.c
 endif
+if NO_FPARSELN
+nodist_tmux_SOURCES += compat/fparseln.c
+endif
 if NO_GETOPT
 nodist_tmux_SOURCES += compat/getopt.c
 endif

cfg.c

@@ -23,7 +23,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <util.h>
 
 #include "tmux.h"
 

compat.h

@@ -239,6 +239,10 @@ int		 vasprintf(char **, const char *, va_list);
 char		*fgetln(FILE *, size_t *);
 #endif
 
+#ifndef HAVE_FPARSELN
+char		*fparseln(FILE *, size_t *, size_t *, const char *, int);
+#endif
+
 #ifndef HAVE_SETENV
 /* setenv.c */
 int		 setenv(const char *, const char *, int);

configure.ac

@@ -295,6 +295,13 @@ if test "x$found_fgetln" = xyes; then
 fi
 AM_CONDITIONAL(NO_FGETLN, [test "x$found_fgetln" = xno])
 
+# Look for fparseln, compat/fparseln.c used if missing.
+AC_CHECK_FUNC(fparseln, found_fparseln=yes, found_fparseln=no)
+if test "x$found_fparseln" = xyes; then
+	AC_DEFINE(HAVE_FPARSELN)
+fi
+AM_CONDITIONAL(NO_FPARSELN, [test "x$found_fparseln" = xno])
+
 # Look for strcasestr, compat/strcasestr.c used if missing.
 AC_CHECK_FUNC(strcasestr, found_strcasestr=yes, found_strcasestr=no)
 if test "x$found_strcasestr" = xyes; then