Why doesn't C++ compile on win (from Git)?

Question

visual studio

I download the repository from the link: https://github.com/IronLynx/maze4d
I install Visual Studio 2015
I try to compile, it gives an error:

1>d:\4dmaze\glad\include\glad\glad.h(47): error C2144: syntax error: 'int' should be preceded by ';'
1>d:\4dmaze\glad\include\glad\glad.h(47): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

Both errors point to this line (46-48):

#ifdef __cplusplus
extern "C" {
#endif

Swap the order of including glad.h so that it ends everywhere.

The error remains the same, but now in the file sal.h on a similar line extern "C" {

1>d:\visualstudio2015\vc\include\sal.h(2361): error C2144: syntax error: 'int' should be preceded by ';'
1>d:\visualstudio2015\vc\include\sal.h(2361): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

The author of the repository compiles everything right away. The question is what am I doing wrong?