build system portability fixes

 * especially to improve building on FreeBSD 11
 * We need GNU Make, yet alone because Scintilla/Scinterm
   needs it. We now document that dependency and added
   an Autoconf check from the autoconf-archive.
   We make sure that the build process is invoked with GNU make
   by generating only GNUmakefiles.
   The Makefile.am files have not been renamed, so this
   change can be rolled back easily.
 * Some GNU-Make-specific autoreconf warnings have still been
   resolved. But not all of them, as this would have been
   unelegant and we need GNU Make anyway.
 * Declare ACLOCAL_AMFLAGS to appease autoreconf
 * Added an explicit check for C++11 from the autoconf-archives.
   In general we should support building with every C++11 compiler
   that is sufficiently GNU-like.
 * Do not use `sed` for inplace editing, as different sed-implementations
   have mutually incompatible syntax for this.
   Instead of declaring and checking a dependency on GNU sed,
   we simply use SciTECO for the editing task.
   This improves code portability on BSDs.
 * Similarily, BSD/POSIX `cmp` is supported now.
   This fixes the test suite on BSD without declaring a
   dependency on the GNU coreutils.
 * Simplified sciteco-wrapper generation.

1 files changed, 20 insertions, 6 deletions

diff --git a/configure.ac b/configure.ac
index c8dab97..928749b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -53,12 +53,24 @@ canonicalize() {
 # Checks for programs.
 LT_INIT
 AC_PROG_CXX
+AX_CXX_COMPILE_STDCXX(11, noext, mandatory)
 AC_PROG_CC
 AC_PROG_CC_C99
-AC_PROG_GREP
 AC_PROG_SED
 AC_PROG_INSTALL
 
+# Mainly because of Scintilla, which depends on
+# GNU Make.
+# The main build system could be made POSIX-Make
+# compliant, but that would complicate it and
+# seems unnecessary.
+# We prevent the main build system from being
+# invoked with another Make by generating GNUmakefiles.
+AX_CHECK_GNU_MAKE
+if [[ x$ax_cv_gnu_make_command = x ]]; then
+	AC_MSG_ERROR([GNU Make required!])
+fi
+
 # Additionally required by the Scintilla build process:
 AC_CHECK_TOOL(AR, ar)
 AC_PROG_RANLIB
@@ -352,9 +364,11 @@ AC_ARG_ENABLE(static-executables,
 	[static_executables=$enableval], [static_executables=no])
 AM_CONDITIONAL(STATIC_EXECUTABLES, [test x$static_executables = xyes])
 
-AC_CONFIG_FILES([Makefile distribute.mk])
-AC_CONFIG_FILES([src/Makefile src/interface-gtk/Makefile src/interface-curses/Makefile])
-AC_CONFIG_FILES([lib/Makefile])
-AC_CONFIG_FILES([doc/Makefile doc/Doxyfile])
-AC_CONFIG_FILES([tests/Makefile tests/atlocal])
+AC_CONFIG_FILES([GNUmakefile:Makefile.in src/GNUmakefile:src/Makefile.in]
+                [src/interface-gtk/GNUmakefile:src/interface-gtk/Makefile.in]
+                [src/interface-curses/GNUmakefile:src/interface-curses/Makefile.in]
+                [lib/GNUmakefile:lib/Makefile.in]
+                [doc/GNUmakefile:doc/Makefile.in doc/Doxyfile]
+                [tests/GNUmakefile:tests/Makefile.in tests/atlocal])
+AC_CONFIG_FILES([distribute.mk], [chmod +x distribute.mk])
 AC_OUTPUT