[svn-r17616] Purpose:

    CFLAGS overhaul

Description:

    Modified the way configure handles CFLAGS.

    (note: all changes also apply to FCFLAGS, CXXFLAGS, CPPFLAGS, and LDFLAGS).

    1. The configure process will now always preserve a user's CFLAGS
    environment variable setup. Any additional flags necessary for compilation
    added at configure time will be passed into the Makefiles as AM_CFLAGS,
    which is an automake construct to be used in addition to CFLAGS.

    This will allow a user to have the final say, as CFLAGS will always appear
    later in the compile line than AM_CFLAGS. Additionally, setting CFLAGS
    during make will no longer completely erase all flags set by configure,
    since they're maintained in AM_CFLAGS.

    2. Additionally, where possible, flags previously being assigned directly
    into CFLAGS (and thus propagating into h5cc) have now been redirected into
    H5_CFLAGS, so they're used ONLY for compiling hdf5, and not embedded into
    the h5cc wrapper script as well.

    *Note that H5_CFLAGS ultimately is assigned into AM_CFLAGS for use in the
    Makefiles. Complete description of changes and build process will be
    included in a Configure Document that Elena and I are working on.

    3. Removed unsupported config files. This includes:

       config/dec-osf*
       config/hpux11.00
       config/irix5.x
       config/powerpc-ibm-aix4.x
       config/rs6000-ibm-aix5.x
       config/unicos*

     4. Modified configure summary to display additional values. Specifically,
     appropriate AM_* variables are being shown, as well as H5_FCFLAGS and
     H5_CXXFLAGS, which were for some reason not already present.

Tested:

    - H5committest
    - Tested on all THG / NCSA machines, using several combinations of the more
      prominent configure options (c++, fortran, szip, threadsafe, parallel,
      et cetera). (Thanks to Quincey for rysnc testing setup!)
    - With regards to new automated testing, anything *necessary* for
      compilation will be caught by the daily tests as it stands now. (i.e.,
      if LDFLAGS is not properly set when szip is used, linking will fail).
      Additionally, with regards to which flags get into h5cc, if any
      *necessary* flags have been improperly removed, then daily tests should
      fail during make installcheck. Additional machine-specific desired
      behaviors and/or checks may have to be set up separately within the
      daily tests, so this is something to work on.

1 files changed, 9 insertions, 7 deletions

diff --git a/config/commence.am b/config/commence.am
index e5e4de9..667dbb2 100644
--- a/config/commence.am
+++ b/config/commence.am
@@ -55,13 +55,15 @@ H5FC_PP=$(bindir)/h5pfc
 H5CPP=$(bindir)/h5c++
   
 
-# H5_CFLAGS holds flags that should be used as CFLAGS when building hdf5,
-# but which shouldn't be exported to h5cc for building other programs.
-
-CFLAGS=@CFLAGS@ @H5_CFLAGS@
-CPPFLAGS=@CPPFLAGS@ @H5_CPPFLAGS@
-FCFLAGS=@FCFLAGS@ @H5_FCFLAGS@
-CXXFLAGS=@CXXFLAGS@ @H5_CXXFLAGS@
+# H5_CFLAGS holds flags that should be used when building hdf5,
+# but which should not be exported to h5cc for building other programs.
+# AM_CFLAGS is an automake construct which should be used by Makefiles 
+# instead of CFLAGS, as CFLAGS is reserved solely for the user to define.
+
+AM_CFLAGS=@AM_CFLAGS@ @H5_CFLAGS@
+AM_FCFLAGS=@AM_FCFLAGS@ @H5_FCFLAGS@
+AM_CXXFLAGS=@AM_CXXFLAGS@ @H5_CXXFLAGS@
+AM_CPPFLAGS=@AM_CPPFLAGS@ @H5_CPPFLAGS@
 
 # The trace script; this is used on source files from the C library to
 # insert tracing macros.