Disable MTPZ support in RHEL

MTPZ is a proprietary protocol and its implementation is based on custom
crypto, which is not desired for RHEL. The Zune service looks dead anyway.

libmtp.spec

@@ -14,7 +14,9 @@ BuildRequires:  gcc
 BuildRequires:  make
 BuildRequires:  libusbx-devel
 BuildRequires:  doxygen
+%if ! 0%{?rhel}
 BuildRequires:  libgcrypt-devel
+%endif
 BuildRequires:  chrpath
 
 Patch0:         0001-doc-Don-t-document-internal-endian-macros.patch
@@ -46,7 +48,11 @@ library for MTP media players.
 
 %build
 %configure --disable-static \
-           --with-udev-rules=69-libmtp.rules
+           --with-udev-rules=69-libmtp.rules \
+%if 0%{?rhel}
+           --disable-mtpz \
+%endif
+            %{nil}
 %make_build
 
 %install
@@ -106,6 +112,7 @@ chrpath --delete $RPM_BUILD_ROOT{%{_bindir},/usr/lib/udev}/mtp*
 %changelog
 * Wed May 26 2021 Ondrej Holy <oholy@redhat.com> - 1.1.18-3
 - Drop redundant devel requires
+- Disable MTPZ support in RHEL
 
 * Tue Jan 26 2021 Fedora Release Engineering <releng@fedoraproject.org> - 1.1.18-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_34_Mass_Rebuild