build: check for libcrypto and libssl

Use PKG_CHECK_MODULES to check for libcrypto and libssl

Change-Id: I442603f9fa3f648cb552f5e9daf6e0fd49776eff
diff --git a/configure.ac b/configure.ac
index 07ea265..16489f4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5,6 +5,10 @@
 AC_PROG_CC
 AC_PROG_LIBTOOL
 
+PKG_CHECK_MODULES(LIBCRYPTO, libcrypto)
+PKG_CHECK_MODULES(LIBSSL, libssl)
+
+
 # zlib support
 AC_CHECK_LIB(z,deflate,ZLIB=yes,ZLIB=no)
 if test "x$ZLIB" = "xyes" ; then