Convert some hardcoded flags to expressions

* Remove the continuable-coroutines interface target

CMakeLists.txt

@@ -38,8 +38,7 @@ target_include_directories(continuable-base
 
 target_link_libraries(continuable-base
   INTERFACE
-    Threads::Threads
-    continuable-coroutines)
+    Threads::Threads)
 
 target_compile_features(continuable-base
   INTERFACE
@@ -57,6 +56,17 @@ target_compile_features(continuable-base
     cxx_trailing_return_types
     cxx_return_type_deduction)
 
+if (CTI_CONTINUABLE_WITH_AWAIT)
+  target_compile_options(continuable-base
+    INTERFACE
+      $<$<CXX_COMPILER_ID:MSVC>:/await>
+      $<$<CXX_COMPILER_ID:CLANG>:-fcoroutines-ts>)
+
+  target_compile_definitions(continuable-base
+    INTERFACE
+      -DCONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
+endif()
+
 add_library(continuable INTERFACE)
 add_library(continuable::continuable ALIAS continuable)
 
@@ -66,7 +76,7 @@ target_link_libraries(continuable
     function2)
 
 # Create an install target
-install(TARGETS continuable-coroutines continuable-base continuable
+install(TARGETS continuable-base continuable
         EXPORT continuable-config
         INCLUDES DESTINATION include)
 

cmake/CMakeLists.txt

@@ -1,6 +1,5 @@
 add_library(continuable-features-flags INTERFACE)
 add_library(continuable-features-warnings INTERFACE)
 add_library(continuable-features-noexcept INTERFACE)
-add_library(continuable-coroutines INTERFACE)
 
 include(cmake/configure_compiler.cmake)

cmake/compiler/clang.cmake

@@ -5,16 +5,6 @@ target_compile_options(continuable-features-warnings
     -pedantic
     -Wextra)
 
-if (CTI_CONTINUABLE_WITH_AWAIT)
-  target_compile_options(continuable-coroutines
-    INTERFACE
-      -fcoroutines-ts)
-
-  target_compile_definitions(continuable-coroutines
-    INTERFACE
-      -DCONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
-endif()
-
 if (CTI_CONTINUABLE_WITH_NO_EXCEPTIONS)
   target_compile_options(continuable-features-noexcept
     INTERFACE

cmake/compiler/msvc.cmake

@@ -19,16 +19,6 @@ target_compile_options(continuable-features-warnings
   INTERFACE
     /W4)
 
-if (CTI_CONTINUABLE_WITH_AWAIT)
-  target_compile_options(continuable-coroutines
-    INTERFACE
-      /await)
-
-  target_compile_definitions(continuable-coroutines
-    INTERFACE
-      -DCONTINUABLE_HAS_EXPERIMENTAL_COROUTINE)
-endif()
-
 if (CTI_CONTINUABLE_WITH_NO_EXCEPTIONS)
   target_compile_definitions(continuable-features-noexcept
     INTERFACE