[libpng16] Updated INSTALL info about pnglibconf.h

This commit is contained in:
Glenn Randers-Pehrson 2014-09-18 09:25:50 -05:00
parent baa95a2d49
commit 44bda93154

15
INSTALL
View File

@ -333,7 +333,7 @@ built. pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
after the build of pnglibconf.h and it is never included in an application
build.
The rarely used alternative of adding a list of feature macros to the
The formerly used alternative of adding a list of feature macros to the
CPPFLAGS setting in the build also still works; however, the macros will be
copied to pnglibconf.h and this may produce macro redefinition warnings
when the individual C files are compiled.
@ -349,12 +349,19 @@ functioning awk called 'nawk'.
Configuration options are now documented in scripts/pnglibconf.dfa. This
file also includes dependency information that ensures a configuration is
consistent; that is, if a feature is switched off dependent features are
also removed. As a recommended alternative to using feature macros in
consistent; that is, if a feature is switched off, dependent features are
also switched off. As a recommended alternative to using feature macros in
pngusr.h a system builder may also define equivalent options in pngusr.dfa
(or, indeed, any file) and add that to the configuration by setting
DFA_XTRA to the file name. The makefiles in contrib/pngminim illustrate
how to do this, and illustrate a case where pngusr.h is still required.
how to do this, and also illustrate a case where pngusr.h is still required.
After you have built libpng, the definitions that were recorded in
pnglibconf.h are available to your application (pnglibconf.h is included
in png.h and gets installed alongside png.h and pngconf.h in your
$PREFIX/include directory). Do not edit pnglibconf.h after you have built
libpng, because than the settings would not accurately reflect the settings
that were used to build libpng.
XV. Configuring libpng for multiprocessing