Add options for custom clang binary path in clang compile config constructor (#143)

include/cppast/libclang_parser.hpp

@@ -95,6 +95,13 @@ public:
     /// and `__cppast_minor__`.
     libclang_compile_config();
 
+    /// Create the default configuration, using a custom path to the clang binary
+    /// \effects It will set the clang binary as passed, or will search for it as normal if not found
+    /// as well as the libclang system include directory determined by the build system.
+    /// It will also define `__cppast__` with the value `"libclang"` as well as `__cppast_major__`
+    /// and `__cppast_minor__`.
+    libclang_compile_config(std::string clang_binary);
+
     /// Creates the configuration stored in the database.
     ///
     /// \effects It will use the options found in the database for the specified file.
@@ -109,6 +116,20 @@ public:
     /// path.
     libclang_compile_config(const libclang_compilation_database& database, const std::string& file);
 
+    /// Creates the configuration stored in the database, using a custom path to the clang binary
+    ///
+    /// \effects It will use the options found in the database for the specified file.
+    /// This does not necessarily need to match the file that is going to be parsed,
+    /// but it should.
+    /// It will also add the default configuration options.
+    /// \notes Header files are not included in the compilation database,
+    /// you need to pass in the file name of the corresponding source file,
+    /// if you want to parse one.
+    /// \notes It will only consider options you could also set by the other functions.
+    /// \notes The file key will include the specified directory in the JSON, if it is not a full
+    /// path.
+    libclang_compile_config(std::string clang_binary, const libclang_compilation_database& database, const std::string& file);
+
     libclang_compile_config(const libclang_compile_config& other) = default;
     libclang_compile_config& operator=(const libclang_compile_config& other) = default;
 

src/libclang/libclang_parser.cpp

@@ -78,12 +78,14 @@ bool libclang_compilation_database::has_config(const char* file_name) const
 namespace
 {} // namespace
 
-libclang_compile_config::libclang_compile_config()
+libclang_compile_config::libclang_compile_config() : libclang_compile_config(CPPAST_CLANG_BINARY) {}
+
+libclang_compile_config::libclang_compile_config(std::string clang_binary)
 : compile_config({}), write_preprocessed_(false), fast_preprocessing_(false),
   remove_comments_in_macro_(false)
 {
     // set given clang binary
-    set_clang_binary(CPPAST_CLANG_BINARY);
+    set_clang_binary(clang_binary);
 
     // set macros to detect cppast
     define_macro("__cppast__", "libclang");
@@ -205,7 +207,14 @@ void parse_flags(CXCompileCommand cmd, Func callback)
 
 libclang_compile_config::libclang_compile_config(const libclang_compilation_database& database,
                                                  const std::string&                   file)
-: libclang_compile_config()
+: libclang_compile_config(CPPAST_CLANG_BINARY, database, file)
+{}
+
+
+cppast::libclang_compile_config::libclang_compile_config(
+    std::string clang_binary, const libclang_compilation_database& database,
+    const std::string& file)
+: libclang_compile_config(clang_binary)
 {
     auto cxcommands
         = clang_CompilationDatabase_getCompileCommands(database.database_, file.c_str());