SoX Fix -- Configure and build

SoX Fix -- Configure and build

Somewhere along the line our SoX code stopped working.  This changeset
brings back SoX support in SXEmacs.

Please Note:  There is now a minimum version required for SoX... 14.1.0

	* m4/sxe-mm.m4 (SXE_CHECK_SOX_LOCATOR): Nuke it.

	* m4/sxe-mm.m4 (SXE_CHECK_SOX_LOCATIONS): Rewrite using pkg-config
	voodoo.

	* m4/sxe-mm.m4 (_SXE_CHECK_SOX): Simplify.  No need to check for
	that st rubbish anymore.

	* m4/sxe-mm.m4 (SXE_CHECK_SOX_HEADERS): Don't look for st.h.

	* m4/sxe-mm.m4 (SXE_CHECK_SOX_LIBS): Remove the st rubbish.

	* m4/sxe-mm.m4 (SXE_CHECK_SOX_STRUCTS): Ditto.
	Check for struct sox_format_t instead of sox_format.

	* src/media/media-sox.c (media_sox_open): HAVE_STRUCT_SOX_FORMAT
	-> HAVE_STRUCT_SOX_FORMAT_T

	* INSTALL (Packages): Mention that the minimum version of SoX is
	now 14.1.0.

	* .gitignore: Ignore anything starting with `=' instead of just
	`=build'. For us crazy folk who have multiple build directories on
	the go at once.

Signed-off-by: Steve Youngs <steve@sxemacs.org>