Bypass autoscan's recommendation of AC_FUNC_MALLOC or AC_FUNC_REALLOC

This should fix https://github.com/fontforge/fontforge/issues/384 in terms
of AC_FUNC_MALLOC and AC_FUNC_REALLOC so if someone runs autoscan it won't
get re-inserted to test for this again.
Allow for clean GCC warnings if libuninames not used here.

Prior GCC cleanup removed them, but they're needed if libuninameslist used.
Merge pull request #386 from JoesCat/master

small detail, but important - need to keep variables that got removed earlier.
Merge pull request #387 from JoesCat/2013mar5_AC_FUNC_REALLOC

Bypass autoscan's recommendation of AC_FUNC_MALLOC or AC_FUNC_REALLOC
rename config.h -> fontforge-config.h
rename two more places
Merge branch 'master' of github.com:coolwanglu/fontforge