gcc/g++ warnings about pdfgen HOT 5 CLOSED

#include "/home/davidoro/libs/PDFGen-master/pdfgen.h"
#include "/home/davidoro/libs/PDFGen-master/pdfgen.c"

int main(int argc, char* argv[]) {
    return 0;
}

In file included from ./main.cpp:3:
/home/davidoro/libs/PDFGen-master/pdfgen.c:101: warning: "_POSIX_SOURCE" redefined
 #define _POSIX_SOURCE     /* For localtime_r */
 
In file included from /usr/include/x86_64-linux-gnu/bits/libc-header-start.h:33,
                 from /usr/include/stdint.h:26,
                 from /usr/lib/gcc/x86_64-linux-gnu/8/include/stdint.h:9,
                 from /home/davidoro/libs/PDFGen-master/pdfgen.h:16,
                 from ./main.cpp:2:
/usr/include/features.h:264: note: this is the location of the previous definition
 # define _POSIX_SOURCE 1
 
In file included from ./main.cpp:3:
/home/davidoro/libs/PDFGen-master/pdfgen.c:102: warning: "_XOPEN_SOURCE" redefined
 #define _XOPEN_SOURCE 600 /* for M_SQRT2 */
 
In file included from /usr/include/x86_64-linux-gnu/bits/libc-header-start.h:33,
                 from /usr/include/stdint.h:26,
                 from /usr/lib/gcc/x86_64-linux-gnu/8/include/stdint.h:9,
                 from /home/davidoro/libs/PDFGen-master/pdfgen.h:16,
                 from ./main.cpp:2:
/usr/include/features.h:203: note: this is the location of the previous definition
 # define _XOPEN_SOURCE 700
 
In file included from ./main.cpp:3:
/home/davidoro/libs/PDFGen-master/pdfgen.c: In function ‘int flexarray_set(flexarray*, int, void*)’:
/home/davidoro/libs/PDFGen-master/pdfgen.c:298:22: error: invalid conversion from ‘void*’ to ‘void***’ [-fpermissive]
         flex->bins = bins;
                      ^~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c:300:19: error: invalid conversion from ‘void*’ to ‘void**’ [-fpermissive]
             calloc(flexarray_get_bin_size(flex, flex->bin_count - 1),
             ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                    sizeof(void *));
                    ~~~~~~~~~~~~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c: In function ‘ssize_t dstr_ensure(dstr*, size_t)’:
/home/davidoro/libs/PDFGen-master/pdfgen.c:362:27: error: invalid conversion from ‘void*’ to ‘char*’ [-fpermissive]
         new_data = realloc(str->data, new_len);
                    ~~~~~~~^~~~~~~~~~~~~~~~~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c: In function ‘pdf_object* pdf_get_object(const pdf_doc*, int)’:
/home/davidoro/libs/PDFGen-master/pdfgen.c:478:25: error: invalid conversion from ‘void*’ to ‘pdf_object*’ [-fpermissive]
     return flexarray_get(&pdf->objects, index);
            ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c: In function ‘pdf_object* pdf_add_object(pdf_doc*, int)’:
/home/davidoro/libs/PDFGen-master/pdfgen.c:525:17: error: invalid conversion from ‘void*’ to ‘pdf_object*’ [-fpermissive]
     obj = calloc(1, sizeof(*obj));
           ~~~~~~^~~~~~~~~~~~~~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c: In function ‘pdf_doc* pdf_create(float, float, const pdf_info*)’:
/home/davidoro/libs/PDFGen-master/pdfgen.c:576:17: error: invalid conversion from ‘void*’ to ‘pdf_doc*’ [-fpermissive]
     pdf = calloc(1, sizeof(*pdf));
           ~~~~~~^~~~~~~~~~~~~~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c:591:23: error: invalid conversion from ‘void*’ to ‘pdf_info*’ [-fpermissive]
     obj->info = calloc(sizeof(*obj->info), 1);
                 ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c: In function ‘int pdf_save_object(pdf_doc*, FILE*, int)’:
/home/davidoro/libs/PDFGen-master/pdfgen.c:805:30: error: invalid conversion from ‘void*’ to ‘pdf_object*’ [-fpermissive]
                 flexarray_get(&object->pag/e.children, i);
                 ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c:834:30: error: invalid conversion from ‘void*’ to ‘pdf_object*’ [-fpermissive]
             f = flexarray_get(&object->bookmark.children, 0);
                 ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c:835:30: error: invalid conversion from ‘void*’ to ‘pdf_object*’ [-fpermissive]
             l = flexarray_get(&object->bookmark.children, nchildren - 1);
                 ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c: In function ‘pdf_object* pdf_add_raw_jpeg(pdf_doc*, const char*)’:
/home/davidoro/libs/PDFGen-master/pdfgen.c:2239:23: error: invalid conversion from ‘void*’ to ‘uint8_t*’ {aka ‘unsigned char*’} [-fpermissive]
     jpeg_data = malloc(len);
                 ~~~~~~^~~~~
/home/davidoro/libs/PDFGen-master/pdfgen.c: In function ‘int pdf_add_ppm(pdf_doc*, pdf_object*, float, float, float, float, const char*)’:
/home/davidoro/libs/PDFGen-master/pdfgen.c:2339:18: error: invalid conversion from ‘void*’ to ‘uint8_t*’ {aka ‘unsigned char*’} [-fpermissive]
     data = malloc(size);
            ~~~~~~^~~~~~