Issues in compiling on Android Studio 3.6

[azghanvi]

I tried compiling it on android studio 3.6, win10 64 bit and found following issues. Also fixed them and logging here to support the community.

1. liblame\machine.h:43:9: error: redeclaration of 'strchr' must have the 'overloadable' attribute
   Fix:

# ifndef HAVE_STRCHR
# // define strchr index // <---- uncomment this.
#  define strchr index
#  define strrchr rindex
# endif

2. id3tag.c:833: error: undefined reference to 'index'
   Fix:
   In jni/Application.mk, add this:
   APP_CFLAGS += -DSTDC_HEADERS

3. sock.c:686:5: error: 'memcpy' will always overflow - destination buffer has size 12, but size argument is 16
   Fix:
   On this line add -4 at end of sizeof. I know it's not a fix but it went through after this. If someone know the solution of Implementation #3, please mention in comments.
   memcpy(&server.sin_addr, &sin.sin_addr, sizeof(struct sockaddr_in)-4);

[mirsamantajbakhsh]

Really sorry. Replying very late. The fix is this:
Change

memcpy(&server.sin_addr, &sin.sin_addr, sizeof(struct sockaddr_in)-4);

to:

memcpy(&server.sin_addr, &sin.sin_addr, sizeof(sin.sin_addr));

Then it will compile.