fix compilation for MSDOS (#3369)

CMakeLists.txt

@@ -99,6 +99,10 @@ set(FMT_SYSTEM_HEADERS_ATTRIBUTE "")
 if (FMT_SYSTEM_HEADERS)
   set(FMT_SYSTEM_HEADERS_ATTRIBUTE SYSTEM)
 endif ()
+if(CMAKE_SYSTEM_NAME STREQUAL "MSDOS")
+  set(FMT_TEST OFF)
+  message(STATUS "MSDOS is incompatible with gtest")
+endif()
 
 # Get version from core.h
 file(READ include/fmt/core.h core_h)

src/os.cc

@@ -372,6 +372,7 @@ file file::open_windows_file(wcstring_view path, int oflag) {
 }
 #  endif
 
+#if !defined(__MSDOS__)
 long getpagesize() {
 #  ifdef _WIN32
   SYSTEM_INFO si;
@@ -384,6 +385,7 @@ long getpagesize() {
   return size;
 #  endif
 }
+#endif
 
 FMT_BEGIN_DETAIL_NAMESPACE