autotools: modified autogen.sh script to be able to build from different directory.

Summary:
Right now we cannot have a designated build directory and build in the same folder as in the source. So modified the autogen.sh so that we can have a designated build directory and can build from that.

@feature

Signed-off-by: Srivardhan Hebbar <sri.hebbar@samsung.com>

Reviewers: cedric, raster, devilhorns

Subscribers: zmike, cedric

Differential Revision: https://phab.enlightenment.org/D1359

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>

autogen.sh

@@ -1,11 +1,17 @@
 #!/bin/sh
 
-rm -rf autom4te.cache
-rm -f aclocal.m4 ltmain.sh config.cache
+test -n "$srcdir" || srcdir=`dirname "$0"`
+test -n "$srcdir" || srcdir=.
+(
+  cd "$srcdir" &&
+  (
+    rm -rf autom4te.cache
+    rm -f aclocal.m4 ltmain.sh config.cache
 
-autoreconf --symlink --install || exit 1
+    autoreconf --symlink --install || exit 1
+  )
+)
+
+test -n "$NOCONFIGURE" || exec $srcdir/configure -C "$@"
 
-if [ -z "$NOCONFIGURE" ]; then
-  exec ./configure -C "$@"
-fi
 exit 0