refactor: move headertest into separate test folder

tests/CMakeLists.txt

 # The main libgit2 tests tree: this CMakeLists.txt includes the
 # subprojects that make up core libgit2 support.
 
+add_subdirectory(headertest)
 add_subdirectory(libgit2)

tests/README.md

@@ -4,6 +4,9 @@ These are the unit and integration tests for the libgit2 projects.
 
 * `clar`  
   This is [clar](https://github.com/clar-test/clar) the common test framework.
+* `headertest`  
+  This is a simple project that ensures that our public headers are
+  compatible with extremely strict compilation options.
 * `libgit2`  
   These tests exercise the core git functionality in libgit2 itself.
 * `resources`  

tests/headertest/CMakeLists.txt

+# Header file validation project: ensure that we do not publish any sloppy
+# definitions in our headers and that a consumer can include <git2.dll>
+# even when they have aggressive C90 warnings enabled.
+
+add_executable(headertest headertest.c)
+set_target_properties(headertest PROPERTIES C_STANDARD 90)
+set_target_properties(headertest PROPERTIES C_EXTENSIONS OFF)
+target_include_directories(headertest PRIVATE ${LIBGIT2_INCLUDES})
+
+if (MSVC)
+	target_compile_options(headertest PUBLIC /W4 /WX)
+else()
+	target_compile_options(headertest PUBLIC -Wall -Wextra -pedantic -Werror)
+endif()

tests/libgit2/CMakeLists.txt

@@ -80,20 +80,3 @@ add_clar_test(ssh                 -v -sonline::push -sonline::clone::ssh_cert -s
 add_clar_test(proxy               -v -sonline::clone::proxy)
 add_clar_test(auth_clone          -v -sonline::clone::cred)
 add_clar_test(auth_clone_and_push -v -sonline::clone::push -sonline::push)
-
-#
-# Header file validation project: ensure that we do not publish any sloppy
-# definitions in our headers and that a consumer can include <git2.dll>
-# even when they have aggressive C90 warnings enabled.
-#
-
-add_executable(headertest headertest.c)
-set_target_properties(headertest PROPERTIES C_STANDARD 90)
-set_target_properties(headertest PROPERTIES C_EXTENSIONS OFF)
-target_include_directories(headertest PRIVATE ${LIBGIT2_INCLUDES})
-
-if (MSVC)
-	target_compile_options(headertest PUBLIC /W4 /WX)
-else()
-	target_compile_options(headertest PUBLIC -Wall -Wextra -pedantic -Werror)
-endif()