WIP: Show all if_xx versions

.travis.yml

@@ -96,7 +96,7 @@ script:
   - if [ "$CHECK_AUTOCONF" = "yes" -a "$CC" = "gcc" ]; then make -C src autoconf; fi
   - if [ "x$SHADOWOPT" != x ]; then make -C src shadow; fi
   - (cd ${SRCDIR} && ./configure --with-features=$FEATURES $CONFOPT --enable-fail-if-missing && if [ "$BUILD" = "yes" ]; then make -j$NPROC; fi)
-  - if [ "$BUILD" = "yes" ]; then ${SRCDIR}/vim --version; fi
+  - if [ "$BUILD" = "yes" ]; then ${SRCDIR}/vim --version; ${SRCDIR}/vim --not-a-term -u NONE -S ${SRCDIR}/testdir/if_ver-1.vim -c quit > /dev/null; ${SRCDIR}/vim --not-a-term -u NONE -S ${SRCDIR}/testdir/if_ver-2.vim -c quit > /dev/null; cat if_ver.txt; fi
   - if [ -n "$ASAN_OPTIONS" ]; then export PATH=/usr/lib/llvm-$(clang -v 2>&1 | sed -n 's/.*version \([1-9]\.[0-9][0-9]*\).*/\1/p')/bin:$PATH; fi
   - make $SHADOWOPT $TEST
   - if [ -n "$ASAN_OPTIONS" ]; then for log in $(find -type f -name 'asan.*' -size +0); do cat "$log"; err=1; done; fi

src/testdir/if_ver-1.vim

@@ -0,0 +1,22 @@
+" Print all interface versions and write the result into if_ver.txt.
+" For Ubuntu. Part 1.
+
+redir! > if_ver.txt
+echo "*** Interface versions ***"
+echo "\nLua:"
+lua print(_VERSION)
+" echo "\nLuaJIT:"
+" lua print(jit.version)
+if has('mzscheme')
+  echo "\nMzScheme:"
+  mzscheme (display (version))
+endif
+echo "\nPerl:"
+perl print $^V
+echo "\nRuby:"
+ruby print RUBY_VERSION
+echo "\nTcl:"
+tcl puts [info patchlevel]
+echo "\nPython 2:"
+python import sys; print sys.version
+redir END

src/testdir/if_ver-2.vim

@@ -0,0 +1,8 @@
+" Print py3 interface version and write the result into if_ver.txt.
+" For Ubuntu. Part 2.
+
+redir! >> if_ver.txt
+echo "\nPython 3:"
+python3 import sys; print(sys.version)
+echo "\n"
+redir END