[PATCH 0/2] add some new autoconf macros for searching the possible warning flags allowed by the current version of the gcc compiler

This patch series introduces some new autoconf macros for searching the possible warning flags allowed by the current version of the gcc compiler. Using these macros it adds a new option --enable-gcc-warnings (default off). There are several possible gcc warnings flags, i have included some of the most useful in my opinion but certainly there are several other perhaps more useful for git, so comments are welcome. Naturally the new macro are not limited only to the portable search of the gcc warning flags or to gcc in first place in any way

Elia Pinto (2):
  configure.ac: add new autoconf macro for checking valid compiler
    flags
  configure.ac: use GIT_CC_CHECK_FLAG_APPEND for adding
    --with-gcc-warnings configure option

 Makefile     |   12 ++++-
 configure.ac |  141 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 149 insertions(+), 4 deletions(-)