Refactor FPM checks (#8)

- Cross-compilation enhancements to be able to set PROC_MEM_FILE
- mach_vm_read check simplified as the signature is a bit different
  vm_map_read_t vs vm_map_t first argument. The `check_symbol_exists()`
  is sufficient check in this case and avoids writing entire signature.
- clock_get*time() check moved to fpm's CMakeLists.txt directly
- Some FPM checks now have a bit simpler configure log/output messages
- The toolchains template improved and refactored
- Fixed some nits in FindNetSnmp module

Author: petk

cmake/cmake/modules/FindNetSnmp.cmake

@@ -5,20 +5,20 @@ Module defines the following `IMPORTED` target(s):
 
 * `NetSnmp::NetSnmp` - The package library, if found.
 
-Result variables:
+## Result variables
 
 * `NetSnmp_FOUND` - Whether the package has been found.
 *` NetSnmp_INCLUDE_DIRS` - Include directories needed to use this package.
 *` NetSnmp_LIBRARIES` - Libraries needed to link to the package library.
 * `NetSnmp_VERSION` - Package version, if found.
 
-Cache variables:
+## Cache variables
 
 * `NetSnmp_INCLUDE_DIR` - Directory containing package library headers.
 * `NetSnmp_LIBRARY` - The path to the package library.
 * `NetSnmp_EXECUTABLE` - Path to net-snmp-config utility.
 
-Hints:
+## Hints
 
 The `NetSnmp_ROOT` variable adds custom search path.
 #]=============================================================================]
@@ -60,13 +60,19 @@ if(NetSnmp_EXECUTABLE)
     string(APPEND _netsnmp_config_include_dir "/include")
   endif()
 
-  # TODO: To be added.
+  # TODO: To be added when linking static NetSnmp library.
   execute_process(
     COMMAND "${NetSnmp_EXECUTABLE}" --external-libs
     OUTPUT_VARIABLE _netsnmp_config_external_libraries
     OUTPUT_STRIP_TRAILING_WHITESPACE
     ERROR_QUIET
   )
+  separate_arguments(
+    _netsnmp_config_external_libraries
+    NATIVE_COMMAND
+    "${_netsnmp_config_external_libraries}"
+  )
+  list(FILTER _netsnmp_config_external_libraries INCLUDE REGEX "^(-L|-l)")
 
   execute_process(
     COMMAND "${NetSnmp_EXECUTABLE}" --libdir

cmake/cmake/modules/PHP/CheckClockGettime.cmake

@@ -1,13 +1,18 @@
 #[=============================================================================[
-Check for items required by listening queue implemented in FPM.
+Check FPM listening queue implementation.
 
-Cache variables:
+## Cache variables
 
 * `HAVE_LQ_TCP_INFO`
+
   Whether `TCP_INFO` is present.
+
 * `HAVE_LQ_TCP_CONNECTION_INFO`
+
   Whether `TCP_CONNECTION_INFO` is present.
+
 * `HAVE_LQ_SO_LISTENQ`
+
   Whether `SO_LISTENQLEN` and `SO_LISTENQLIMIT` are available as alternative to
   `TCP_INFO` and `TCP_CONNECTION_INFO`.
 #]=============================================================================]
@@ -18,7 +23,8 @@ include(CheckSourceCompiles)
 include(CMakePushCheckState)
 include(PHP/SystemExtensions)
 
-message(CHECK_START "Checking for TCP_INFO")
+message(CHECK_START "Checking FPM listening queue implementation")
+
 cmake_push_check_state(RESET)
   # Requires _DEFAULT_SOURCE, which is enabled by _GNU_SOURCE.
   set(CMAKE_REQUIRED_LIBRARIES PHP::SystemExtensions)
@@ -36,36 +42,26 @@ cmake_push_check_state(RESET)
     }
   ]] HAVE_LQ_TCP_INFO)
 cmake_pop_check_state()
-if(HAVE_LQ_TCP_INFO)
-  message(CHECK_PASS "yes")
-else()
-  message(CHECK_FAIL "no")
-endif()
 
 # For macOS.
-message(CHECK_START "Checking for TCP_CONNECTION_INFO")
-check_source_compiles(C [[
-  #include <netinet/tcp.h>
-
-  int main(void)
-  {
-    struct tcp_connection_info ti;
-    int x = TCP_CONNECTION_INFO;
-    (void)ti;
-    (void)x;
-
-    return 0;
-  }
-]] HAVE_LQ_TCP_CONNECTION_INFO)
-if(HAVE_LQ_TCP_CONNECTION_INFO)
-  message(CHECK_PASS "yes")
-else()
-  message(CHECK_FAIL "no")
+if(NOT HAVE_LQ_TCP_INFO)
+  check_source_compiles(C [[
+    #include <netinet/tcp.h>
+
+    int main(void)
+    {
+      struct tcp_connection_info ti;
+      int x = TCP_CONNECTION_INFO;
+      (void)ti;
+      (void)x;
+
+      return 0;
+    }
+  ]] HAVE_LQ_TCP_CONNECTION_INFO)
 endif()
 
 # For FreeBSD.
-if(NOT HAVE_LQ_TCP_INFO AND NOT HAVE_LQ_TCP_CONNECTION_INFO)
-  message(CHECK_START "Checking for SO_LISTENQLEN and SO_LISTENQLIMIT")
+if(NOT HAVE_LQ_TCP_INFO AND NOT HAVE_LQ_TCP_INFO)
   check_source_compiles(C [[
     #include <sys/socket.h>
 
@@ -79,9 +75,10 @@ if(NOT HAVE_LQ_TCP_INFO AND NOT HAVE_LQ_TCP_CONNECTION_INFO)
       return 0;
     }
   ]] HAVE_LQ_SO_LISTENQ)
-  if(HAVE_LQ_SO_LISTENQ)
-    message(CHECK_PASS "yes")
-  else()
-    message(CHECK_FAIL "no")
-  endif()
+endif()
+
+if(HAVE_LQ_TCP_INFO OR HAVE_LQ_TCP_CONNECTION_INFO OR HAVE_LQ_SO_LISTENQ)
+  message(CHECK_PASS "found")
+else()
+  message(CHECK_FAIL "not found, FPM listening queue is disabled")
 endif()