[CMake] config.h, part 2 - full compatibility with autoconf.

This commit makes the file config.h generated by CMake 100% compatible
with the one generated by autoconf/configure.

Fixes in this commit:
 - Set FLTK_DATADIR and FLTK_DOCDIR with the same default values.
   Note: needs some cleanup, option values are not clear, '/fltk'
   is currently appended in export.cmake (needs improvement).
 - Simulation of autoconf macro AC_HEADER_DIRENT for correct
   definition of only one 'dirent' header file.
 - Fix more function checks:
    - dlsym
    - png_get_valid
    - png_set_tRNS_to_alpha
 - Improve "Big Endian" check for __APPLE__ (mac_endianness.h).


git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10985 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 48 insertions, 8 deletions

diff --git a/CMake/resources.cmake b/CMake/resources.cmake
index 730f19070..0218813c9 100644
--- a/CMake/resources.cmake
+++ b/CMake/resources.cmake
@@ -22,26 +22,41 @@
 #######################################################################
 # headers
 find_file(HAVE_ALSA_ASOUNDLIB_H alsa/asoundlib.h)
-find_file(HAVE_DIRENT_H dirent.h)
 find_file(HAVE_DLFCN_H dlfcn.h)
 find_file(HAVE_FREETYPE_H freetype.h PATH_SUFFIXES freetype2 freetype2/freetype)
 find_file(HAVE_GL_GL_H GL/gl.h)
 find_file(HAVE_GL_GLU_H GL/glu.h)
 find_file(HAVE_LIBPNG_PNG_H libpng/png.h)
 find_file(HAVE_LOCALE_H locale.h)
-find_file(HAVE_NDIR_H ndir.h)
 find_file(HAVE_OPENGL_GLU_H OpenGL/glu.h)
 find_file(HAVE_PNG_H png.h)
 find_file(HAVE_PTHREAD_H pthread.h)
 find_file(HAVE_STDIO_H stdio.h)
 find_file(HAVE_STRINGS_H strings.h)
-find_file(HAVE_SYS_DIR_H sys/dir.h)
-find_file(HAVE_SYS_NDIR_H sys/ndir.h)
 find_file(HAVE_SYS_SELECT_H sys/select.h)
 find_file(HAVE_SYS_STDTYPES_H sys/stdtypes.h)
 find_file(HAVE_X11_XREGION_H X11/Xregion.h)
 find_path(HAVE_XDBE_H Xdbe.h PATH_SUFFIXES X11/extensions extensions)
 
+# Simulate the behavior of autoconf macro AC_HEADER_DIRENT, see:
+# https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Particular-Headers.html
+# "Check for the following header files. For the first one that is found
+#  and defines ‘DIR’, define the listed C preprocessor macro ..."
+#
+# Note: we don't check if it really defines 'DIR', but we stop processing
+# once we found the first suitable header file.
+
+find_file(HAVE_DIRENT_H dirent.h)
+if(NOT HAVE_DIRENT_H)
+  find_file(HAVE_SYS_NDIR_H sys/ndir.h)
+  if(NOT HAVE_SYS_NDIR_H)
+    find_file(HAVE_SYS_DIR_H sys/dir.h)
+    if(NOT HAVE_SYS_DIR_H)
+      find_file(HAVE_NDIR_H ndir.h)
+    endif(NOT HAVE_SYS_DIR_H)
+  endif(NOT HAVE_SYS_NDIR_H)
+endif(NOT HAVE_DIRENT_H)
+
 mark_as_advanced(HAVE_ALSA_ASOUNDLIB_H HAVE_DIRENT_H HAVE_DLFCN_H)
 mark_as_advanced(HAVE_FREETYPE_H HAVE_GL_GL_H HAVE_GL_GLU_H)
 mark_as_advanced(HAVE_LIBPNG_PNG_H HAVE_LOCALE_H HAVE_NDIR_H)
@@ -79,15 +94,32 @@ mark_as_advanced(LIB_jpeg LIB_png LIB_zlib)
 # functions
 include(CheckFunctionExists)
 
+# save CMAKE_REQUIRED_LIBRARIES (is this really necessary ?)
+if(DEFINED CMAKE_REQUIRED_LIBRARIES)
+  set(SAVED_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
+else(DEFINED CMAKE_REQUIRED_LIBRARIES)
+  unset(SAVED_REQUIRED_LIBRARIES)
+endif(DEFINED CMAKE_REQUIRED_LIBRARIES)
+set(CMAKE_REQUIRED_LIBRARIES)
+
 if(HAVE_DLFCN_H)
    set(HAVE_DLFCN_H 1)
 endif(HAVE_DLFCN_H)
-CHECK_FUNCTION_EXISTS(dlsym                  HAVE_DLSYM)
 
-CHECK_FUNCTION_EXISTS(localeconv             HAVE_LOCALECONV)
+if(LIB_dl)
+  set(CMAKE_REQUIRED_LIBRARIES ${LIB_dl})
+  CHECK_FUNCTION_EXISTS(dlsym			HAVE_DLSYM)
+  set(CMAKE_REQUIRED_LIBRARIES)
+endif(LIB_dl)
 
-CHECK_FUNCTION_EXISTS(png_get_valid          HAVE_PNG_GET_VALID)
-CHECK_FUNCTION_EXISTS(png_set_tRNS_to_alpha  HAVE_PNG_SET_TRNS_TO_ALPHA)
+CHECK_FUNCTION_EXISTS(localeconv		HAVE_LOCALECONV)
+
+if(LIB_png)
+  set(CMAKE_REQUIRED_LIBRARIES ${LIB_png})
+  CHECK_FUNCTION_EXISTS(png_get_valid		HAVE_PNG_GET_VALID)
+  CHECK_FUNCTION_EXISTS(png_set_tRNS_to_alpha	HAVE_PNG_SET_TRNS_TO_ALPHA)
+  set(CMAKE_REQUIRED_LIBRARIES)
+endif(LIB_png)
 
 CHECK_FUNCTION_EXISTS(scandir                HAVE_SCANDIR)
 CHECK_FUNCTION_EXISTS(snprintf               HAVE_SNPRINTF)
@@ -120,6 +152,14 @@ if(HAVE_SCANDIR AND NOT HAVE_SCANDIR_POSIX)
 endif(HAVE_SCANDIR AND NOT HAVE_SCANDIR_POSIX)
 mark_as_advanced(HAVE_SCANDIR_POSIX)
 
+# restore CMAKE_REQUIRED_LIBRARIES (is this really necessary ?)
+if(DEFINED SAVED_REQUIRED_LIBRARIES)
+  set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
+  unset(SAVED_REQUIRED_LIBRARIES)
+else(DEFINED SAVED_REQUIRED_LIBRARIES)
+  unset(CMAKE_REQUIRED_LIBRARIES)
+endif(DEFINED SAVED_REQUIRED_LIBRARIES)
+
 #######################################################################
 # packages