Add support for libsecret to cmake

gnucash has historically supported storing passwords for database
backends with libsecret when HAVE_LIBSECRET is defined. The code is
still present, but support for detecting libsecret's availablity was not
ported over when the build system was converted to cmake.  This change
restores the missing detection.

CMakeLists.txt

@@ -505,6 +505,11 @@ find_program(POD2MAN_EXECUTABLE pod2man HINTS ${PERL_DIR})
 gnc_pkg_check_modules (ICU4C REQUIRED icu-uc)
 gnc_pkg_check_modules (ICU4C_I18N REQUIRED icu-i18n)
 
+GNC_PKG_CHECK_MODULES (LIBSECRET libsecret-1>=0.18)
+IF (LIBSECRET_FOUND)
+  SET (HAVE_LIBSECRET ON)
+ENDIF (LIBSECRET_FOUND)
+
 #BOOST
 set (Boost_USE_MULTITHREADED ON)
 set (Boost_FIND_QUIETLY ON)

cmake/README_CMAKE.txt

@@ -45,9 +45,8 @@ Limitations include:
   * Not all options available in `./configure` have been ported to
     this CMake system.
 
-  * Password management is included for OS X, but not
-    tested. Gnome-keyring and libsecret support has not
-    been ported over.
+  * Password management is included for OS X and libsecret, but not
+    tested. Gnome-keyring support has not been ported over.
 
   * The Xcode build only supports the Debug configuration. Others such
     as Release are not supported yet.

gnucash/gnome-utils/CMakeLists.txt

@@ -212,7 +212,7 @@ add_library (gncmod-gnome-utils
 )
 
 target_link_libraries(gncmod-gnome-utils gncmod-app-utils gncmod-engine gnc-backend-xml-utils
-     ${CMAKE_DL_LIBS} ${GTK3_LDFLAGS} ${GTK_MAC_LDFLAGS})
+     ${CMAKE_DL_LIBS} ${GTK3_LDFLAGS} ${LIBSECRET_LDFLAGS} ${GTK_MAC_LDFLAGS})
 
 target_compile_definitions(gncmod-gnome-utils PUBLIC ${GTK_MAC_CFLAGS_OTHER}
   PRIVATE -DG_LOG_DOMAIN=\"gnc.gui\")
@@ -232,6 +232,7 @@ target_include_directories(gncmod-gnome-utils
       ${CMAKE_CURRENT_SOURCE_DIR}
     PRIVATE
       ${GTK_MAC_INCLUDE_DIRS}
+      ${LIBSECRET_INCLUDE_DIRS}
       ${CMAKE_CURRENT_BINARY_DIR}
 )