Bug#971810: engrampa FTCBFS: AC_RUN_IFELSE

[Helmut Grohne <helmut@subdivi.de>]

Source: engrampa
Version: 1.24.1-1
Tags: patch upstream
User: debian-cross@lists.debian.org
Usertags: ftcbfs

engrampa fails to cross build from source, because it uses a run check
to discover the behaviour of file wrt zstd. This has two problems:
 A) It uses AC_RUN_IFELSE, which breaks cross compilation.
 B) It checks the version of file used during build. Not the one it is
    working with.

I'm attaching a patch that makes it simply assume a recent file during
cross compilation and we can be done with that. My solution leaves
aspect B) unaddressed. Please close this bug even if not solving B).

For solving B), there are a number of options. A simple one is issuing a
runtime dependency on libmagic1 (>= 1:5.38). Then you always have the
fixed libmagic and nothing to worry about.

This doesn't work upstream however. For upstream there also is a better
solution. Instead of checking the behaviour of file at build time, you
can check the version of file at runtime. You can simply call
magic_version() in the application.

Just some thoughts. The bug is really about A).

Helmut

--- engrampa-1.24.1.orig/configure.ac
+++ engrampa-1.24.1/configure.ac
@@ -190,9 +190,15 @@
     }
     return status;]])],
 		[zstd_mime_type="application/x-zstd"],
-		[zstd_mime_type="application/zstd"]
+		[zstd_mime_type="application/zstd"],
+		[zstd_mime_type="cross"]
 	)
-	AC_MSG_RESULT($zstd_mime_type)
+	AS_IF([test "$zstd_mime_type" = "cross"],[
+		zstd_mime_type="application/x-zstd"
+		AC_MSG_RESULT(cross, guessing $zstd_mime_type)
+	],[
+		AC_MSG_RESULT($zstd_mime_type)
+	])
 	dnl *******************************************
 
 	LIBS="$save_LIBS"