Fix support for CMake unity builds

Author: vector-of-bool

CMakeLists.txt

@@ -67,8 +67,12 @@ if(PROJECT_IS_TOP_LEVEL)
     )
 endif()
 
-# When compiling C++ with GCC, set a deeper diagnostics depth
-add_compile_options($<$<AND:$<CXX_COMPILER_ID:GNU>,$<COMPILE_LANGUAGE:CXX>>:-fconcepts-diagnostics-depth=4>)
+add_compile_options(
+    # When compiling C++ with GCC, set a deeper diagnostics depth
+    $<$<AND:$<CXX_COMPILER_ID:GNU>,$<COMPILE_LANGUAGE:CXX>>:-fconcepts-diagnostics-depth=4>
+    # Enable large object files with MSVC
+    $<$<CXX_COMPILER_ID:MSVC>:/bigobj>
+)
 
 # If we generate any DLLs, use a .dll.lib suffix for the importlibs, to distinguish
 # them from actual static libraries

tools/GenURITests.cmake

@@ -31,6 +31,10 @@ set(GenURITests_HEAD [[// clang-format off
 
 using namespace amongoc;
 
+// Guard this section to support unity builds involving these files
+#ifndef URI_TESTS_COMMON_BLOCK
+#define URI_TESTS_COMMON_BLOCK
+
 inline std::variant<string, int> w_parameter(int n) {
     return n;
 }
@@ -73,6 +77,9 @@ consteval server_monitoring_mode smm(std::string_view sv) {
         throw;
     }
 }
+
+#endif // URI_TESTS_COMMON_BLOCK
+
 ]])
 
 set(__param_canon_spelling [[{