Re-do the broken-nice() patch to break less platforms. Hopefully none :P

Also note that it isn't just Linux nice() that is broken: at least FreeBSD
and BSDI also have this problem. os.nice() should probably just be emulated
using getpriority()/setpriority(), if they are available, but I'll get to
that later.

Modules/posixmodule.c

@@ -1110,6 +1110,12 @@ posix_mkdir(PyObject *self, PyObject *args)
 
 
 #ifdef HAVE_NICE
+#if defined(HAVE_BROKEN_NICE) && defined(HAVE_SYS_RESOURCE_H)
+#if defined(HAVE_GETPRIORITY) && !defined(PRIO_PROCESS)
+#include <sys/resource.h>
+#endif
+#endif
+
 static char posix_nice__doc__[] =
 "nice(inc) -> new_priority\n\
 Decrease the priority of process and return new priority.";
@@ -1124,8 +1130,8 @@ posix_nice(PyObject *self, PyObject *args)
 
 	/* There are two flavours of 'nice': one that returns the new
 	   priority (as required by almost all standards out there) and the
-	   Linux one, which returns '0' on success and advices the use of
-	   getpriority() to get the new priority.
+	   Linux/FreeBSD/BSDI one, which returns '0' on success and advices
+	   the use of getpriority() to get the new priority.
 	   
 	   If we are of the nice family that returns the new priority, we
 	   need to clear errno before the call, and check if errno is filled
@@ -1134,7 +1140,7 @@ posix_nice(PyObject *self, PyObject *args)
 
 	errno = 0;
 	value = nice(increment);
-#ifdef HAVE_GETPRIORITY
+#if defined(HAVE_BROKEN_NICE) && defined(HAVE_GETPRIORITY)
 	if (value == 0)
 		value = getpriority(PRIO_PROCESS, 0);
 #endif

acconfig.h

@@ -116,6 +116,9 @@
 /* Define as the size of the unicode type. */
 #undef Py_UNICODE_SIZE
 
+/* Define if nice() returns success/failure instead of the new priority. */
+#undef HAVE_BROKEN_NICE
+
 /* Define if malloc(0) returns a NULL pointer */
 #undef MALLOC_ZERO_RETURNS_NULL
 

config.h.in

@@ -175,6 +175,9 @@
 /* Define as the size of the unicode type. */
 #undef Py_UNICODE_SIZE
 
+/* Define if nice() returns success/failure instead of the new priority. */
+#undef HAVE_BROKEN_NICE
+
 /* Define if malloc(0) returns a NULL pointer */
 #undef MALLOC_ZERO_RETURNS_NULL
 
@@ -641,6 +644,9 @@
 /* Define if you have the <sys/param.h> header file.  */
 #undef HAVE_SYS_PARAM_H
 
+/* Define if you have the <sys/resource.h> header file.  */
+#undef HAVE_SYS_RESOURCE_H
+
 /* Define if you have the <sys/select.h> header file.  */
 #undef HAVE_SYS_SELECT_H
 

configure

 #! /bin/sh
 
-# From configure.in Revision: 1.225 
+# From configure.in Revision: 1.226 
 
 # Guess values for system-dependent variables and create Makefiles.
 # Generated automatically using autoconf version 2.13 
@@ -2074,7 +2074,7 @@ signal.h stdarg.h stddef.h stdlib.h thread.h unistd.h utime.h termios.h \
 sys/audioio.h sys/file.h sys/lock.h sys/modem.h db_185.h db.h \
 sys/param.h sys/select.h sys/socket.h sys/time.h sys/times.h \
 sys/un.h sys/utsname.h sys/wait.h pty.h libutil.h \
-ndbm.h db1/ndbm.h gdbm/ndbm.h
+ndbm.h db1/ndbm.h gdbm/ndbm.h sys/resource.h
 do
 ac_safe=`echo "$ac_hdr" | sed 'y%./+-%__p_%'`
 echo $ac_n "checking for $ac_hdr""... $ac_c" 1>&6
@@ -6876,6 +6876,51 @@ else
 fi
 
 
+echo $ac_n "checking for broken nice()""... $ac_c" 1>&6
+echo "configure:6881: checking for broken nice()" >&5
+if eval "test \"`echo '$''{'ac_cv_broken_nice'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+  
+if test "$cross_compiling" = yes; then
+    { echo "configure: error: can not run test program while cross compiling" 1>&2; exit 1; }
+else
+  cat > conftest.$ac_ext <<EOF
+#line 6890 "configure"
+#include "confdefs.h"
+
+int main()
+{
+	int val1 = nice(1);
+	if (val1 != -1 && val1 == nice(2))
+		exit(0);
+	exit(1);
+}
+
+EOF
+if { (eval echo configure:6902: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext} && (./conftest; exit) 2>/dev/null
+then
+  ac_cv_broken_nice=yes
+else
+  echo "configure: failed program was:" >&5
+  cat conftest.$ac_ext >&5
+  rm -fr conftest*
+  ac_cv_broken_nice=no
+fi
+rm -fr conftest*
+fi
+
+fi
+
+echo "$ac_t""$ac_cv_broken_nice" 1>&6
+if test "$ac_cv_broken_nice" = yes
+then
+  cat >> confdefs.h <<\EOF
+#define HAVE_BROKEN_NICE 1
+EOF
+
+fi
+
 # THIS MUST BE LAST, IT CAN BREAK OTHER TESTS!
 # Add sys/socket.h to confdefs.h
 cat >> confdefs.h <<\EOF
@@ -6884,12 +6929,12 @@ cat >> confdefs.h <<\EOF
 #endif
 EOF
 echo $ac_n "checking for socklen_t""... $ac_c" 1>&6
-echo "configure:6888: checking for socklen_t" >&5
+echo "configure:6933: checking for socklen_t" >&5
 if eval "test \"`echo '$''{'ac_cv_type_socklen_t'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 6893 "configure"
+#line 6938 "configure"
 #include "confdefs.h"
 #include <sys/types.h>
 #if STDC_HEADERS
@@ -6938,7 +6983,7 @@ done
 
 SRCDIRS="Parser Grammar Objects Python Modules"
 echo $ac_n "checking for build directories""... $ac_c" 1>&6
-echo "configure:6942: checking for build directories" >&5
+echo "configure:6987: checking for build directories" >&5
 for dir in $SRCDIRS; do
     if test ! -d $dir; then
         mkdir $dir

configure.in

@@ -545,7 +545,7 @@ signal.h stdarg.h stddef.h stdlib.h thread.h unistd.h utime.h termios.h \
 sys/audioio.h sys/file.h sys/lock.h sys/modem.h db_185.h db.h \
 sys/param.h sys/select.h sys/socket.h sys/time.h sys/times.h \
 sys/un.h sys/utsname.h sys/wait.h pty.h libutil.h \
-ndbm.h db1/ndbm.h gdbm/ndbm.h)
+ndbm.h db1/ndbm.h gdbm/ndbm.h sys/resource.h)
 AC_HEADER_DIRENT
 
 # checks for typedefs
@@ -1671,6 +1671,23 @@ fi
 AC_CHECK_LIB(readline, rl_completion_matches,
 	AC_DEFINE(HAVE_RL_COMPLETION_MATCHES), , -ltermcap)
 
+AC_MSG_CHECKING(for broken nice())
+AC_CACHE_VAL(ac_cv_broken_nice, [
+AC_TRY_RUN([
+int main()
+{
+	int val1 = nice(1);
+	if (val1 != -1 && val1 == nice(2))
+		exit(0);
+	exit(1);
+}
+],ac_cv_broken_nice=yes, ac_cv_broken_nice=no)])
+AC_MSG_RESULT($ac_cv_broken_nice)
+if test "$ac_cv_broken_nice" = yes
+then
+  AC_DEFINE(HAVE_BROKEN_NICE)
+fi
+
 # THIS MUST BE LAST, IT CAN BREAK OTHER TESTS!
 # Add sys/socket.h to confdefs.h
 cat >> confdefs.h <<\EOF