Remove configure.in to configure.ac

This is the extension expected by all non-ancient autoconf versions.

docs/contributing/about-platform-toolkit-and-library-names.md

@@ -75,7 +75,7 @@ compatibility is maintained between point releases (those with the same
 major.minor number).
 
 A known break in binary compatibility should be addressed by updating
-the library soname (see the notes in configure.in for details on this).
+the library soname (see the notes in configure.ac for details on this).
 
 --------------------------------------------------------------------
 

docs/contributing/about-version-numbers.md

@@ -16,7 +16,7 @@ instructions there.
 Here is the list of files that need to be updated:
 
 - build/bakefiles/version.bkl {C:R:A}          [NOT UPDATED AUTOMATICALLY]
-- configure.in
+- configure.ac
 - build/osx/wxvers.xcconfig
 - docs/changes.txt
 - docs/readme.txt (date needs manual editing)  [NOT UPDATED AUTOMATICALLY]

docs/contributing/how-to-add-files-to-build-system.md

@@ -180,11 +180,11 @@ d) Modify multilib.bkl to add files to multilib build: add foolib and foodll
 
 e) Regenerate all makefiles (don't forget to run autoconf)
 
-f) Update configure.in and wx-config.in to contain information about
+f) Update configure.ac and wx-config.in to contain information about
    the library and needed linker flags:
-   * Add "foo" to `BUILT_WX_LIBS` in configure.in.
+   * Add "foo" to `BUILT_WX_LIBS` in configure.ac.
    * If appropriate, but it rarely is, so normally this should _not_ be done,
-     add "foo" to either `STD_BASE_LIBS` or `STD_GUI_LIBS` in configure.in.
+     add "foo" to either `STD_BASE_LIBS` or `STD_GUI_LIBS` in configure.ac.
    * If wxFoo links against additional libraries, add necessary linker
      flags and libraries to ldflags_foo and ldlibs_foo variables in
      wx-config.in (both are optional).

docs/contributing/how-to-add-new-sample.md

@@ -36,15 +36,15 @@ samples/ with demos/ where needed).
       compiler (run `bakefile --help` to get the list of possible values).
       Again, see `how-to-add-files-to-build-system.md` for more information.
 
-4. Modify configure.in Unix compilation:
+4. Modify configure.ac Unix compilation:
    - if the sample should only be built if `wxUSE_FOO` is enabled, locate
-      the test for `wxUSE_FOO = yes` in configure.in and add a line
+      the test for `wxUSE_FOO = yes` in configure.ac and add a line
       `SAMPLES_SUBDIRS="$SAMPLES_SUBDIRS foo"` under it
    - if it should be always built, locate the line `if test $wxUSE_GUI = yes`
-     near the end of configure.in and modify the assignment to
+     near the end of configure.ac and modify the assignment to
      `SAMPLES_SUBDIRS` to include "foo" (put in alphabetical order)
 
-   After this, regenerate configure from configure.in
+   After this, regenerate configure from configure.ac
    by running "autoconf" on a Unix system in the corresponding directory.
 
 5. Modify `build/cmake/samples/CMakeLists.txt` to include the sample in

docs/contributing/how-to-add-new-wxUSE_XXX.md

@@ -58,7 +58,7 @@ The following files need to be modified when adding a new `wxUSE_FOO`:
    These options won't be defined for the other ports, so shouldn't be added to
    the common `include/wx/chkconf.h` but to this file instead.
 
-- `configure.in`
+- `configure.ac`
 
    Here you need to add `DEFAULT_wxUSE_FOO` define. It should be added in the
    block beginning after `WX_ARG_CACHE_INIT` line and should default to "no" for

docs/x11/install.md

@@ -393,7 +393,7 @@ automatically using wx-config
 2. The other way creates a project within the source code
 directories of wxWidgets. For this endeavour, you'll need
 GNU autoconf version 2.14 and add an entry to your Makefile.in
-to the bottom of the configure.in script and run autoconf
+to the bottom of the configure.ac script and run autoconf
 and configure before you can type make.
 
 Further notes by Julian Smart          {#x11_notes}