py/misc: Fix msvc compilation with compressed error messages.

py/misc.h

@@ -293,15 +293,16 @@ typedef union _mp_float_union_t {
 
 // Force usage of the MP_ERROR_TEXT macro by requiring an opaque type.
 typedef struct {
-    #ifdef __clang__
-    // Fix "error: empty struct has size 0 in C, size 1 in C++".
+    #if defined(__clang__) || defined(_MSC_VER)
+    // Fix "error: empty struct has size 0 in C, size 1 in C++", and the msvc counterpart
+    // "C requires that a struct or union have at least one member"
     char dummy;
     #endif
 } *mp_rom_error_text_t;
 
 #include <string.h>
 
-inline __attribute__((always_inline)) const char *MP_COMPRESSED_ROM_TEXT(const char *msg) {
+inline MP_ALWAYSINLINE const char *MP_COMPRESSED_ROM_TEXT(const char *msg) {
     // "genhdr/compressed.data.h" contains an invocation of the MP_MATCH_COMPRESSED macro for each compressed string.
     // The giant if(strcmp) tree is optimized by the compiler, which turns this into a direct return of the compressed data.
     #define MP_MATCH_COMPRESSED(a, b) if (strcmp(msg, a) == 0) { return b; } else