bug#20332: 24.5; With jpeg-6b configure says "WARNING: libjpeg found, but not version 6b or later"

[Glenn Morris]

> $ echo 'version 6b or later' > aaa_emacs-24.5.c; cc -E aaa_emacs-24.5.c
> # 1 "aaa_emacs-24.5.c"
> "aaa_emacs-24.5.c", line 1: invalid input token: 6b
> version  6b or later
> #ident "acomp: Sun C 5.9 SunOS_i386 Patch 124868-01 2007/07/12"
> cc: acomp failed for aaa_emacs-24.5.c
> $ echo $?
> 2

Funnily enough, our own etc/PROBLEMS file used to contain a solution for
this very issue:

    *** `configure' fails with ``"junk.c", line 660: invalid input token: 
8.elc''

    The final stage of the Emacs configure process uses the C preprocessor
    to generate the Makefiles.  Errors of this form can occur if the C
    preprocessor inserts extra whitespace into its output.  The solution
    is to find the switches that stop your preprocessor from inserting extra
    whitespace, add them to CPPFLAGS, and re-run configure.  For example,
    this error can occur on Solaris 10 when using the Sun Studio compiler
    ``Sun C 5.8'' with its preprocessor CPP="/opt/SUNWspro/bin/cc -E".
    The relevant switch in this case is "-Xs" (``compile assuming
    (pre-ANSI) K & R C style code'').

And indeed adding -Xs seems to avoid the issue.

I don't think this is a real solution to this case,
just a historical curiosity. :)