--- CMakeLists.txt.orig	2020-03-27 08:07:31 UTC
+++ CMakeLists.txt
@@ -65,6 +65,7 @@ include(TranslateDesktop)
 include(DefineCMakeDefaults)
 include(DefineCompilerFlags)
 include(DefineInstallationPaths)
+include(FindPkgConfig)
 include(CPackConfig.cmake)
 include(ConfigureChecks.cmake)
 
@@ -167,7 +168,10 @@ find_package(Qt5WebEngineWidgets    REQUIRED)
 find_package(Qt5Qml                 REQUIRED)
 find_package(Qt5Help                REQUIRED)
 find_package(GDAL                   REQUIRED)
-find_package(PROJ4                  REQUIRED)
+find_package(PROJ4)
+if (NOT PROJ4_FOUND)
+  pkg_search_module(PROJ4 REQUIRED proj)
+endif()
 find_package(JPEG                   REQUIRED)
 find_package(ROUTINO                REQUIRED)
 find_package(QuaZip5                REQUIRED)