Added workaround for when Poco*Config.cmake recipes cannot be found.

src/lib/CMakeLists.txt

@@ -3,7 +3,7 @@ include(GNUInstallDirs)
 find_package(PkgConfig REQUIRED)
 pkg_check_modules(libxdg-basedir REQUIRED IMPORTED_TARGET libxdg-basedir)
 find_package(ICU COMPONENTS uc i18n REQUIRED)
-find_package(Poco COMPONENTS Net NetSSL Util CONFIG REQUIRED)
+find_package(Poco COMPONENTS Net NetSSL Util CONFIG) # Not required, see below.
 
 file(GLOB_RECURSE sources_lib *.cpp)
 file(GLOB_RECURSE headers_lib ../../include/*.hpp)
@@ -22,10 +22,29 @@ target_include_directories(${PROJECT_NAME}
   "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>")
 
 target_link_libraries(${PROJECT_NAME}
-  PRIVATE
-  PkgConfig::libxdg-basedir ICU::uc ICU::i18n Poco::Net Poco::NetSSL Poco::Util
+  PRIVATE PkgConfig::libxdg-basedir ICU::uc ICU::i18n
   PUBLIC vsqlitepp stdc++fs)
 
+# Debian Stretch does not contain Poco*Config.cmake recipes.
+if(PocoNetSSL_FOUND)
+  target_link_libraries(${PROJECT_NAME}
+    PRIVATE Poco::Net Poco::NetSSL Poco::Util)
+else()
+  find_file(Poco_h NAMES "Poco/Poco.h"
+    PATHS ${CMAKE_INSTALL_INCLUDEDIR})
+
+  if("${Poco_h}" STREQUAL "Poco_h-NOTFOUND")
+    message(FATAL_ERROR "Could not find POCO.")
+  else()
+    message(WARNING
+      "Your distribution of POCO doesn't contain the *Config.cmake recipes, "
+      "but the files seem to be in the standard directories. "
+      "Let's hope this works.")
+    target_link_libraries(${PROJECT_NAME}
+      PRIVATE PocoNet PocoNetSSL PocoUtil)
+  endif()
+endif()
+
 install(TARGETS ${PROJECT_NAME}
   EXPORT "${PROJECT_NAME}Targets"
   LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"