cmake: fix build without pkg-config (issue #2424)

CMakeLists.txt

@@ -142,16 +142,19 @@ endif()
 #
 ###############################################################################
 
-if(NOT CPPAN_BUILD)
-    find_package(PkgConfig)
-    if (NOT Leptonica_DIR AND NOT MSVC AND COMMAND pkg_check_modules)
-        if(NOT PKG_CONFIG_EXECUTABLE)
-            message(FATAL_ERROR "Missing required pkg-config")
+if(NOT CPPAN_BUILD AND NOT Leptonica_DIR)
+    find_package(Leptonica ${MINIMUM_LEPTONICA_VERSION} CONFIG QUIET)
+    if (NOT Leptonica_FOUND)
+        find_package(PkgConfig QUIET)
+        if(PKG_CONFIG_EXECUTABLE)
+            pkg_check_modules(Leptonica REQUIRED lept>=${MINIMUM_LEPTONICA_VERSION})
+            link_directories(${Leptonica_LIBRARY_DIRS})
+        endif(PKG_CONFIG_EXECUTABLE)
+        # message ("Leptonica: ${Leptonica_LIBRARY_DIRS}, ${Leptonica_FOUND}")
+
+        if (NOT Leptonica_FOUND)
+            message(FATAL_ERROR "Cannot find required library Leptonica. Quitting!")
         endif()
-        pkg_check_modules(Leptonica REQUIRED lept>=${MINIMUM_LEPTONICA_VERSION})
-        link_directories(${Leptonica_LIBRARY_DIRS})
-    else()
-        find_package(Leptonica ${MINIMUM_LEPTONICA_VERSION} REQUIRED CONFIG)
     endif()
 else()
     if (STATIC)