Link against libcrypto, not all of openssl

In the previous build setup, libkmod.so would link to not just
libcrypto.so, but also libssl.so:

$ readelf -d /lib/libkmod.so | grep NEEDED
 0x0000000000000001 (NEEDED)             Shared library: [liblzma.so.5]
 0x0000000000000001 (NEEDED)             Shared library: [libz.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libssl.so.1.1]
 0x0000000000000001 (NEEDED)             Shared library: [libcrypto.so.1.1]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]

We don't need any symbols from libssl, though. This patch ensures that
we pass 'libcrypto' to pkgconfig rather than 'openssl', getting only the
library that we need:

$ readelf -d  ./libkmod/.libs/libkmod.so.2.3.4 | grep NEEDED
 0x0000000000000001 (NEEDED)             Shared library: [liblzma.so.5]
 0x0000000000000001 (NEEDED)             Shared library: [libz.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libcrypto.so.1.1]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
diff --git a/configure.ac b/configure.ac
index ee72283..dffe278 100644
--- a/configure.ac
+++ b/configure.ac
@@ -110,12 +110,12 @@
 	AS_HELP_STRING([--with-openssl], [handle PKCS7 signatures @<:@default=disabled@:>@]),
 	[], [with_openssl=no])
 AS_IF([test "x$with_openssl" != "xno"], [
-	PKG_CHECK_MODULES([openssl], [openssl >= 1.1.0])
+	PKG_CHECK_MODULES([libcrypto], [libcrypto >= 1.1.0])
 	AC_DEFINE([ENABLE_OPENSSL], [1], [Enable openssl for modinfo.])
 ], [
 	AC_MSG_NOTICE([openssl support not requested])
 ])
-CC_FEATURE_APPEND([with_features], [with_openssl], [OPENSSL])
+CC_FEATURE_APPEND([with_features], [with_openssl], [LIBCRYPTO])
 
 AC_ARG_WITH([bashcompletiondir],
 	AS_HELP_STRING([--with-bashcompletiondir=DIR], [Bash completions directory]),