[win] Don't build a custom nanosleep() when not needed

CMakeLists.txt

@@ -220,9 +220,6 @@ if(WIN32)
     find_package(dlfcn-win32 REQUIRED)
     set(CMAKE_DL_LIBS dlfcn-win32::dl)
   endif()
-  if(MINGW)
-    string(REPLACE "iconv" "pthread" MLT_PTHREAD_LIBS "${Iconv_LIBRARY}")
-  endif()
 endif()
 
 find_package(SDL2)

src/framework/CMakeLists.txt

@@ -133,8 +133,13 @@ set_target_properties(mlt PROPERTIES
 )
 
 if(WIN32)
+  include(CheckSymbolExists)
+  set(CMAKE_REQUIRED_LIBRARIES Threads::Threads)
+  check_symbol_exists(nanosleep "pthread.h;pthread_time.h" HAVE_PTHREAD_NANOSLEEP_WIN32)
+  unset(CMAKE_REQUIRED_LIBRARIES)
+
   if(MINGW)
-    target_link_libraries(mlt PRIVATE ${MLT_PTHREAD_LIBS})
+    target_link_libraries(mlt PRIVATE Threads::Threads)
     target_link_options(mlt PRIVATE -Wl,--output-def,${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/libmlt-${MLT_VERSION_MAJOR}.def)
     install(FILES "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/libmlt-${MLT_VERSION_MAJOR}.def" DESTINATION ${CMAKE_INSTALL_LIBDIR})
   endif()
@@ -145,6 +150,8 @@ if(WIN32)
   endif()
 endif()
 
+configure_file(mlt_config.h.in ${CMAKE_CURRENT_BINARY_DIR}/mlt_config.h)
+
 if(NOT (WIN32 OR RELOCATABLE))
   if(APPLE)
     target_compile_definitions(mlt PRIVATE PREFIX_DATA="${CMAKE_INSTALL_FULL_DATADIR}/mlt" PREFIX_LIB="${CMAKE_INSTALL_FULL_LIBDIR}/mlt")
@@ -167,6 +174,7 @@ install(TARGETS mlt
 
 # Install the generated export header
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/mlt_export.h 
+              ${CMAKE_CURRENT_BINARY_DIR}/mlt_config.h
   DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/mlt-${MLT_VERSION_MAJOR}/framework
 )
 

src/framework/mlt_config.h.in

@@ -0,0 +1,4 @@
+/* mlt_config.h.  Generated by cmake from mlt_config.h.in */
+
+/* Defined when a pthread library has an implementation for nanosleep() (win32-only) */
+#cmakedefine HAVE_PTHREAD_NANOSLEEP_WIN32

src/framework/mlt_types.h

@@ -332,12 +332,13 @@ typedef void *(*mlt_thread_function_t)(void *);      /**< generic thread functio
 #endif
 
 #ifdef _WIN32
+#include "mlt_config.h"
 #include <pthread.h>
 /* Win32 compatibility function declarations */
 #if !defined(__MINGW32__)
 MLT_EXPORT int usleep(unsigned int useconds);
 #endif
-#ifndef WIN_PTHREADS_TIME_H
+#ifndef HAVE_PTHREAD_NANOSLEEP_WIN32
 MLT_EXPORT int nanosleep(const struct timespec *rqtp, struct timespec *rmtp);
 #endif
 MLT_EXPORT int setenv(const char *name, const char *value, int overwrite);

src/melt/CMakeLists.txt

@@ -7,12 +7,12 @@ target_link_libraries(melt PRIVATE mlt Threads::Threads)
 target_compile_definitions(melt PRIVATE VERSION="${MLT_VERSION}")
 
 if(SDL2_FOUND AND NOT ANDROID)
-    target_link_libraries(melt PRIVATE SDL2::SDL2)
     target_compile_definitions(melt PRIVATE HAVE_SDL2)
     if(MINGW)
-        target_link_libraries(melt PRIVATE ${MLT_PTHREAD_LIBS})
         target_compile_definitions(melt PRIVATE main=SDL_main)
-        target_link_libraries(melt PRIVATE mingw32 SDL2main SDL2)
+        target_link_libraries(melt PRIVATE mingw32 SDL2::SDL2main SDL2::SDL2)
+    else()
+        target_link_libraries(melt PRIVATE SDL2::SDL2)
     endif()
 endif()
 

src/modules/avformat/CMakeLists.txt

@@ -46,9 +46,6 @@ endif()
 
 if(WIN32)
   target_compile_definitions(mltavformat PRIVATE AVDATADIR="share/ffmpeg/")
-  if(MINGW)
-    target_link_libraries(mltavformat PRIVATE ${MLT_PTHREAD_LIBS})
-  endif()
 endif()
 
 if(USE_AVDEVICE AND AVDEVICE_FOUND)

src/modules/sdl2/CMakeLists.txt

@@ -20,10 +20,6 @@ else()
   target_link_libraries(mltsdl2 PRIVATE m)
 endif()
 
-if(MINGW)
-  target_link_libraries(mltsdl2 PRIVATE ${MLT_PTHREAD_LIBS})
-endif()
-
 set_target_properties(mltsdl2 PROPERTIES LIBRARY_OUTPUT_DIRECTORY "${MLT_MODULE_OUTPUT_DIRECTORY}")
 
 install(TARGETS mltsdl2 LIBRARY DESTINATION ${MLT_INSTALL_MODULE_DIR})

src/win32/win32.c

@@ -29,6 +29,7 @@
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <mlt_config.h>
 #include "../framework/mlt_properties.h"
 #include "../framework/mlt_log.h"
 
@@ -46,7 +47,7 @@ int usleep(unsigned int useconds)
 	return 0;
 }
 
-#ifndef WIN_PTHREADS_TIME_H
+#ifndef HAVE_PTHREAD_NANOSLEEP_WIN32
 int nanosleep(const struct timespec * rqtp, struct timespec * rmtp)
 {
 	if (rqtp->tv_nsec > 999999999) {