Revert "always and only build docs"

This reverts commit cdda3d34a3.

Makefile.am

@@ -1,7 +1,19 @@
 # This Makefile.am is in the public domain
 AM_CPPFLAGS = -I$(top_srcdir)/src/include
 
-SUBDIRS = . contrib src doc
+if DOC_ONLY
+if ENABLE_DOC
+  SUBDIRS = . contrib doc
+else
+  SUBDIRS = . contrib
+endif
+else
+if ENABLE_DOC
+  SUBDIRS = . contrib src doc
+else
+  SUBDIRS = . contrib src
+endif
+endif
 
 BUILT_SOURCES = src/include/taler_error_codes.h
 

configure.ac

@@ -48,6 +48,18 @@ DX_INIT_DOXYGEN([taler-exchange],,,
  DX_CHI_FEATURE(OFF),
  DX_XML_FEATURE(OFF))
 
+AC_MSG_CHECKING([whether to compile documentation ONLY])
+AC_ARG_ENABLE([only-doc],
+  [AS_HELP_STRING([--enable-only-doc], [only compile Taler documentation])],
+  [doc_only=${enableval}],
+  [doc_only=no])
+AC_MSG_RESULT($doc_only)
+AM_CONDITIONAL([DOC_ONLY], [test "x$doc_only" = "xyes"])
+
+
+# Not indented, as most of the file falls under this one...
+AS_IF([test "x$doc_only" != xyes],[
+
 # Checks for programs.
 
 AC_PROG_CC
@@ -489,6 +501,32 @@ AC_TYPE_UINTMAX_T
 # Checks for library functions.
 AC_CHECK_FUNCS([strdup])
 
+
+AC_ARG_ENABLE([[doc]],
+  [AS_HELP_STRING([[--disable-doc]], [do not build any documentation])], ,
+    [enable_doc=yes])
+test "x$enable_doc" = "xno" || enable_doc=yes
+AM_CONDITIONAL([ENABLE_DOC], [test "x$enable_doc" = "xyes"])
+
+
+],[  # This is the big test "$doc_only" on top of the file!
+
+
+# logic if doc_only is set, make sure conditionals are still defined
+AM_CONDITIONAL([HAVE_EXPENSIVE_TESTS], [false])
+AM_CONDITIONAL([MHD_HAVE_EPOLL], [false])
+AM_CONDITIONAL([HAVE_POSTGRESQL], [false])
+AM_CONDITIONAL([HAVE_SQLITE], [false])
+AM_CONDITIONAL([HAVE_LIBCURL], [false])
+AM_CONDITIONAL([HAVE_LIBGNURL], [false])
+AM_CONDITIONAL([HAVE_DEVELOPER], [false])
+AM_CONDITIONAL([USE_COVERAGE], [false])
+AM_CONDITIONAL([ENABLE_DOC], [true])
+AM_CONDITIONAL([HAVE_TWISTER], [false])
+
+# end of 'doc_only'
+])
+
 AC_CONFIG_FILES([Makefile
                  contrib/Makefile
                  doc/Makefile