Add access to source entry point in C API.

glslang/CInterface/glslang_c_interface.cpp

diff --git a/glslang/CInterface/glslang_c_interface.cpp b/glslang/CInterface/glslang_c_interface.cpp
index aafe6c9..a8392ec 100644
--- a/glslang/CInterface/glslang_c_interface.cpp
+++ b/glslang/CInterface/glslang_c_interface.cpp
@@ -352,6 +352,10 @@
     shader->shader->setPreamble(s);
 }
 
+GLSLANG_EXPORT void glslang_shader_set_source_entry_point(glslang_shader_t* shader, const char* s) {
+    shader->shader->setSourceEntryPoint(s);
+}
+
 GLSLANG_EXPORT void glslang_shader_set_entry_point(glslang_shader_t* shader, const char* s) {
     shader->shader->setEntryPoint(s);
 }

glslang/Include/glslang_c_interface.h

diff --git a/glslang/Include/glslang_c_interface.h b/glslang/Include/glslang_c_interface.h
index 41d0da9..3247555 100644
--- a/glslang/Include/glslang_c_interface.h
+++ b/glslang/Include/glslang_c_interface.h
@@ -254,6 +254,9 @@
 GLSLANG_EXPORT glslang_shader_t* glslang_shader_create(const glslang_input_t* input);
 GLSLANG_EXPORT void glslang_shader_delete(glslang_shader_t* shader);
 GLSLANG_EXPORT void glslang_shader_set_preamble(glslang_shader_t* shader, const char* s);
+// Set a different entry point than main in GLSL that will be renamed to value set by glslang_shader_set_entry_point (SPIRV only).
+GLSLANG_EXPORT void glslang_shader_set_source_entry_point(glslang_shader_t* shader, const char* s);
+// Set a different entry point than main in output target (SPIRV only).
 GLSLANG_EXPORT void glslang_shader_set_entry_point(glslang_shader_t* shader, const char* s);
 GLSLANG_EXPORT void glslang_shader_set_invert_y(glslang_shader_t* shader, bool y);
 GLSLANG_EXPORT void glslang_shader_shift_binding(glslang_shader_t* shader, glslang_resource_type_t res, unsigned int base);