Include SDL2 CFlags in with the general CFlags: this fixes SDL2 build…

… failures on macOS.

Regenerate auto-conf/etc.
Fix the SDL2 includes.

Makefile.in

@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.15 from Makefile.am.
+# Makefile.in generated by automake 1.16.3 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2014 Free Software Foundation, Inc.
+# Copyright (C) 1994-2020 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -133,7 +133,7 @@ am__recursive_targets = \
   $(RECURSIVE_CLEAN_TARGETS) \
   $(am__extra_recursive_targets)
 AM_RECURSIVE_TARGETS = $(am__recursive_targets:-recursive=) TAGS CTAGS \
-	cscope distdir dist dist-all distcheck
+	cscope distdir distdir-am dist dist-all distcheck
 am__tagged_files = $(HEADERS) $(SOURCES) $(TAGS_FILES) $(LISP)
 # Read a list of newline-separated strings from the standard input,
 # and print each of them once, without duplicates.  Input order is
@@ -196,6 +196,8 @@ am__relativize = \
 DIST_ARCHIVES = $(distdir).tar.gz
 GZIP_ENV = --best
 DIST_TARGETS = dist-gzip
+# Exists only to be overridden by the user if desired.
+AM_DISTCHECK_DVI_TARGET = dvi
 distuninstallcheck_listfiles = find . -type f -print
 am__distuninstallcheck_listfiles = $(distuninstallcheck_listfiles) \
   | sed 's|^\./|$(prefix)/|' | grep -v '$(infodir)/dir$$'
@@ -342,8 +344,8 @@ Makefile: $(srcdir)/Makefile.in $(top_builddir)/config.status
 	    echo ' $(SHELL) ./config.status'; \
 	    $(SHELL) ./config.status;; \
 	  *) \
-	    echo ' cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__depfiles_maybe)'; \
-	    cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__depfiles_maybe);; \
+	    echo ' cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__maybe_remake_depfiles)'; \
+	    cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__maybe_remake_depfiles);; \
 	esac;
 
 $(top_builddir)/config.status: $(top_srcdir)/configure $(CONFIG_STATUS_DEPENDENCIES)
@@ -461,7 +463,10 @@ distclean-tags:
 	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
 	-rm -f cscope.out cscope.in.out cscope.po.out cscope.files
 
-distdir: $(DISTFILES)
+distdir: $(BUILT_SOURCES)
+	$(MAKE) $(AM_MAKEFLAGS) distdir-am
+
+distdir-am: $(DISTFILES)
 	$(am__remove_distdir)
 	test -d "$(distdir)" || mkdir "$(distdir)"
 	@srcdirstrip=`echo "$(srcdir)" | sed 's/[].[^$$\\*]/\\\\&/g'`; \
@@ -526,7 +531,7 @@ distdir: $(DISTFILES)
 	  ! -type d ! -perm -444 -exec $(install_sh) -c -m a+r {} {} \; \
 	|| chmod -R a+r "$(distdir)"
 dist-gzip: distdir
-	tardir=$(distdir) && $(am__tar) | GZIP=$(GZIP_ENV) gzip -c >$(distdir).tar.gz
+	tardir=$(distdir) && $(am__tar) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).tar.gz
 	$(am__post_remove_distdir)
 
 dist-bzip2: distdir
@@ -541,6 +546,10 @@ dist-xz: distdir
 	tardir=$(distdir) && $(am__tar) | XZ_OPT=$${XZ_OPT--e} xz -c >$(distdir).tar.xz
 	$(am__post_remove_distdir)
 
+dist-zstd: distdir
+	tardir=$(distdir) && $(am__tar) | zstd -c $${ZSTD_CLEVEL-$${ZSTD_OPT--19}} >$(distdir).tar.zst
+	$(am__post_remove_distdir)
+
 dist-tarZ: distdir
 	@echo WARNING: "Support for distribution archives compressed with" \
 		       "legacy program 'compress' is deprecated." >&2
@@ -552,7 +561,7 @@ dist-shar: distdir
 	@echo WARNING: "Support for shar distribution archives is" \
 	               "deprecated." >&2
 	@echo WARNING: "It will be removed altogether in Automake 2.0" >&2
-	shar $(distdir) | GZIP=$(GZIP_ENV) gzip -c >$(distdir).shar.gz
+	shar $(distdir) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).shar.gz
 	$(am__post_remove_distdir)
 
 dist-zip: distdir
@@ -570,7 +579,7 @@ dist dist-all:
 distcheck: dist
 	case '$(DIST_ARCHIVES)' in \
 	*.tar.gz*) \
-	  GZIP=$(GZIP_ENV) gzip -dc $(distdir).tar.gz | $(am__untar) ;;\
+	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).tar.gz | $(am__untar) ;;\
 	*.tar.bz2*) \
 	  bzip2 -dc $(distdir).tar.bz2 | $(am__untar) ;;\
 	*.tar.lz*) \
@@ -580,9 +589,11 @@ distcheck: dist
 	*.tar.Z*) \
 	  uncompress -c $(distdir).tar.Z | $(am__untar) ;;\
 	*.shar.gz*) \
-	  GZIP=$(GZIP_ENV) gzip -dc $(distdir).shar.gz | unshar ;;\
+	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).shar.gz | unshar ;;\
 	*.zip*) \
 	  unzip $(distdir).zip ;;\
+	*.tar.zst*) \
+	  zstd -dc $(distdir).tar.zst | $(am__untar) ;;\
 	esac
 	chmod -R a-w $(distdir)
 	chmod u+w $(distdir)
@@ -598,7 +609,7 @@ distcheck: dist
 	    $(DISTCHECK_CONFIGURE_FLAGS) \
 	    --srcdir=../.. --prefix="$$dc_install_base" \
 	  && $(MAKE) $(AM_MAKEFLAGS) \
-	  && $(MAKE) $(AM_MAKEFLAGS) dvi \
+	  && $(MAKE) $(AM_MAKEFLAGS) $(AM_DISTCHECK_DVI_TARGET) \
 	  && $(MAKE) $(AM_MAKEFLAGS) check \
 	  && $(MAKE) $(AM_MAKEFLAGS) install \
 	  && $(MAKE) $(AM_MAKEFLAGS) installcheck \
@@ -759,7 +770,7 @@ uninstall-am:
 	am--refresh check check-am clean clean-cscope clean-generic \
 	cscope cscopelist-am ctags ctags-am dist dist-all dist-bzip2 \
 	dist-gzip dist-lzip dist-shar dist-tarZ dist-xz dist-zip \
-	distcheck distclean distclean-generic distclean-tags \
+	dist-zstd distcheck distclean distclean-generic distclean-tags \
 	distcleancheck distdir distuninstallcheck dvi dvi-am html \
 	html-am info info-am install install-am install-data \
 	install-data-am install-dvi install-dvi-am install-exec \