build: support static dispatch builds

In order to support the MUSL Linux SDK, we need to ensure that we are
able to build libdispatch statically. Add support to correctly build the
static library on all platforms.

Author: compnerd

dispatch/base.h

@@ -194,7 +194,7 @@
 # endif
 #else
 # if defined(_WIN32)
-#   if defined(dispatch_EXPORT) || defined(__DISPATCH_BUILDING_DISPATCH__)
+#   if defined(dispatch_EXPORTS)
 #     define DISPATCH_EXPORT DISPATCH_EXTERN __declspec(dllexport)
 #   else
 #     define DISPATCH_EXPORT DISPATCH_EXTERN __declspec(dllimport)

src/CMakeLists.txt

@@ -92,6 +92,10 @@ target_include_directories(dispatch PUBLIC
 target_include_directories(dispatch PRIVATE
   ${PROJECT_SOURCE_DIR}/private)
 
+if(NOT BUILD_SHARED_LIBS)
+  target_compile_definitions(dispatch PUBLIC
+    dispatch_STATIC)
+endif()
 if(WIN32)
   target_compile_definitions(dispatch PRIVATE
     _CRT_NONSTDC_NO_WARNINGS

tests/CMakeLists.txt

@@ -23,6 +23,8 @@ add_library(bsdtests
             STATIC
               bsdtests.c
               dispatch_test.c)
+target_link_libraries(bsdtests PUBLIC
+  dispatch)
 target_include_directories(bsdtests
                            PRIVATE
                              ${CMAKE_CURRENT_BINARY_DIR}