Error out of configure if wxwin.m4 was not found by aclocal

[benjaminpjones]

#239

Background

If wxwin.m4 is not found at the autoreconf --install step, configure will silently fall back to the nographics build. It is relatively easy for wxwin.m4 to get missed by aclocal - in my case, the homebrew wx-widgets package stores wxwin.m4 outside the default aclocal search path.

Currently, we get an AC_MSG_NOTICE, but it is easy to miss given that there is a lot logged and reconf exits successfully.

Proposed change

Instead of silently degrading, error out with a message to the user with suggested fixes:

• explicitly select nographics build (--disable-wx)
• ensure wxWidgets installed
• set ACLOCAL_PATH before running autoreconf

Tested

--enable-wx errors

$ ./configure --enable-wx
   ... output omitted for brevity ...
checking enable_wx... yes
configure: error: aclocal did not find wxwin.m4, so wxWidgets cannot be detected.
If wxWidgets is already installed, wxwin.m4 is outside aclocal's search path.
Re-run autoreconf with ACLOCAL_PATH set to the directory holding wxwin.m4.

Or configure with --disable-wx to build without graphics.

--disable-wx configures successfully

$ ./configure --disable-wx
   ... output omitted for brevity ...
checking enable_wx... no
   ... output omitted for brevity
$ echo $?
0

[jrincayc]

I have reviewed and approve.