Allow Mercurial to build on HP-UX 11

Temporary fix to allow Mercurial to build on HP-UX 11, as the C
compiler on HP-UX 11 doesn't support 'inline' qualifier. The
'__inline' qualifier seemed to be supported, but not without
first resolving other associated issues.

mercurial/bdiff.c

@@ -12,6 +12,11 b''
 #include <Python.h>
 #include <stdlib.h>
 #include <string.h>
+
+#ifdef __hpux
+#define inline
+#endif
+
 #ifdef _WIN32
 #ifdef _MSC_VER
 #define inline __inline