Use C wrapper by default

Author: Carlos Une

src/c.c

@@ -1,9 +1,3 @@
-/* FIXME: fpm --flag '-DENABLE_C_WRAPPER' currently doesn't work with .c files. Use #if..#endif below for the time being. */
-#if ((defined(_WIN32) && (defined(__MINGW32__) || defined(__MINGW64__))) || defined(__linux__) || defined(__APPLE__) || defined(__OpenBSD__))
-#define ENABLE_C_WRAPPER
-#endif
-
-#ifdef ENABLE_C_WRAPPER
 #include <sys/stat.h>
 #include <dirent.h>
 
@@ -18,5 +12,3 @@ const char *get_d_name(struct dirent *d)
 {
     return (const char *) d->d_name;
 }
-
-#endif

src/fpm_filesystem.F90

@@ -17,7 +17,7 @@ module fpm_filesystem
 
     integer, parameter :: LINE_BUFFER_LEN = 1000
 
-#ifdef ENABLE_C_WRAPPER
+#ifndef FPM_BOOTSTRAP
     interface
         function c_opendir(dir) result(r) bind(c, name="opendir")
             import c_char, c_ptr
@@ -345,7 +345,7 @@ subroutine mkdir(dir)
     end if
 end subroutine mkdir
 
-#ifdef ENABLE_C_WRAPPER
+#ifndef FPM_BOOTSTRAP
 !> Get file & directory names in directory `dir` using iso_c_binding.
 !!
 !!  - File/directory names return are relative to cwd, ie. preprended with `dir`