MDEV-7066 No Source RPMs ... (and so no "yum-builddep MariaDB-server" either)

create source RPM cpack-way

when building binary packages, this source rpm will use
same BUILD_CONFIG and WITH_SSL values that were used when
creating the source RPM.

Only do it for a reasonably new cmake, where
source rpms are known to work (3.10.2 is ok, 3.5.2 is not).

And force a shorter CPACK_RPM_BUILD_SOURCE_DIRS_PREFIX so that
a source rpm could be built from a standard location in /usr/src

cmake/cpack_rpm.cmake

@@ -260,5 +260,24 @@ ENDIF(compat_rpm)
 SET(CPACK_RPM_compat_PACKAGE_PROVIDES "mysql-libs = 5.3.5") # exact version doesn't matter as long as it greater than 5.1
 SET(CPACK_RPM_compat_PACKAGE_OBSOLETES "mysql-libs < 5.3.5")
 
-ENDIF(RPM)
+################
+IF(CMAKE_VERSION VERSION_GREATER "3.9.99")
+
+SET(CPACK_SOURCE_GENERATOR "RPM")
+SETA(CPACK_RPM_SOURCE_PKG_BUILD_PARAMS
+  "-DBUILD_CONFIG=mysql_release"
+  "-DRPM=${RPM}"
+  "-DCPACK_RPM_BUILD_SOURCE_DIRS_PREFIX=/usr/src/debug/${CPACK_RPM_PACKAGE_NAME}-${VERSION}"
+  )
+
+MACRO(ADDIF var)
+  IF(DEFINED ${var})
+    SETA(CPACK_RPM_SOURCE_PKG_BUILD_PARAMS "-D${var}=${${var}}")
+  ENDIF()
+ENDMACRO()
 
+ADDIF(BUILD_CONFIG)
+ADDIF(WITH_SSL)
+
+ENDIF()
+ENDIF(RPM)