Allow atblgen to process sequence_order.in with empty lines in between lines for building on Macos (#2718)

The present changes are a direct copy-paste from https://github.com/zeldaret/mm/pull/1850

This fixes building on macos due to a kinda specific issue with Apple clang.

When trying to build on Macos (specifically MacOS 12, Monteray with Apple clang 13.0.0 (clang-1300.0.29.30), idk if other versions have this issue too) `make` stops with the following error from `atblgen`:
```
Failed to match line 1: ""
regexec error: "regexec() failed to match"
Error: Malformed build/n64-us/assets/audio/sequence_order.in?
```

`atblgen` makes the assumption that the `sequence_order.in` file has no extra data, spaces, empty lines, etc. but the file somehow ends up having empty lines between each line on macos.

This file is created by using the C preprocessor to process `include/tables/sequence_table.h`.
In normal circumstances this file should look like this snip,
```
(Sequence_0,NA_BGM_GENERAL_SFX)
(Sequence_1,NA_BGM_AMBIENCE)
(Sequence_2,NA_BGM_TERMINA_FIELD)
(Sequence_3,NA_BGM_CHASE)
(Sequence_4,NA_BGM_MAJORAS_THEME)
```
but it ends up looking like this instead
```
(Sequence_0,NA_BGM_GENERAL_SFX)

(Sequence_1,NA_BGM_AMBIENCE)

(Sequence_2,NA_BGM_TERMINA_FIELD)

(Sequence_3,NA_BGM_CHASE)

(Sequence_4,NA_BGM_MAJORAS_THEME)
```
which `atblgen` doesn't like.

I believe this happens because there are lines with comments between each macro in [`sequence_table.h`](https://github.com/zeldaret/mm/blob/0877ce4adf28a8e73e05c3c58682273b8bf28749/include/tables/sequence_table.h) and for some reason this Apple clang version decided to preserve those empty lines

The fix just makes `atblgen` skip empty lines.

I threw `atblgen` to valgrind to check the fix was working as intended and noted a bunch of memory that was being free before exit, so I fixed them.

I also noted the tools/audio makefile was not using `OPTFLAGS` when building those tools, so I fixed that too.

tools/audio/Makefile

@@ -46,7 +46,7 @@ sfc_LDFLAGS     := $(XML_LDFLAGS)
 
 define COMPILE =
 $(1): $($1_SOURCES)
-	$(CC) $(CFLAGS) $($1_CFLAGS) $$^ $($1_LDFLAGS) -o $$@
+	$(CC) $(CFLAGS) $(OPTFLAGS) $($1_CFLAGS) $$^ $($1_LDFLAGS) -o $$@
 endef
 
 $(foreach p,$(PROGRAMS),$(eval $(call COMPILE,$(p))))

tools/audio/aifc.c

@@ -96,8 +96,12 @@ f64_to_f80(double f64, uint8_t *f80)
     } f80tmp;
 
     // get f64 bits
-
-    uint64_t f64_bits = *(uint64_t *)&f64;
+    union {
+        double f;
+        uint64_t u;
+    } tp;
+    tp.f = f64;
+    uint64_t f64_bits = tp.u;
 
     int f64_sgn = F64_GET_SGN(f64_bits);
     int f64_exponent = F64_GET_EXP(f64_bits);
@@ -155,8 +159,12 @@ f80_to_f64(double *f64, uint8_t *f80)
                         ((uint64_t)f64_mantissa_hi << 32) | ((uint64_t)f64_mantissa_lo);
 
     // write double
-
-    *f64 = *(double *)&f64_bits;
+    union {
+        double f;
+        uint64_t u;
+    } tp;
+    tp.u = f64_bits;
+    *f64 = tp.f;
 }
 
 static void

tools/audio/audio_tablegen.c

@@ -300,14 +300,25 @@ read_seq_order(struct seq_order *order, const char *path)
     UNUSED size_t data_size;
     char *filedata = util_read_whole_file(path, &data_size);
 
-    // We expect one entry per line, gather the total length
+    // We expect one entry per line (with the exception of empty lines), gather the total length
     size_t total_size = 0;
-    for (char *p = filedata; *p != '\0'; p++) {
+    char *p = filedata;
+    // Skip empty lines at the beginning of the file
+    while (*p == '\n') {
+        p++;
+    }
+    while (*p != '\0') {
         if (*p == '\n') {
             total_size++;
+            // Skip empty lines
+            while (*p == '\n') {
+                p++;
+            }
         } else if (isspace(*p)) {
             // There should be no whitespace in the input file besides newlines
             goto malformed;
+        } else {
+            p++;
         }
     }
 
@@ -334,6 +345,10 @@ read_seq_order(struct seq_order *order, const char *path)
 
     char *lstart = filedata;
     for (size_t i = 0; i < total_size; i++) {
+        // find next nonempty line
+        while (*lstart == '\n') {
+            lstart++;
+        }
         // find end of line
         char *p = lstart;
         while (*p != '\n') {
@@ -369,6 +384,7 @@ read_seq_order(struct seq_order *order, const char *path)
         lstart = lend + 1;
     }
     assert(*lstart == '\0');
+    regfree(&re);
 
     // Write results
     order->num_sequences = total_size;
@@ -379,9 +395,16 @@ malformed:
     error("Malformed %s?", path);
 }
 
+static void
+free_seq_order(struct seq_order *order)
+{
+    free(order->entries);
+    free(order->filedata);
+}
+
 struct seqdata {
-    const char *elf_path;
-    const char *name;
+    char *elf_path;
+    char *name;
     uint32_t font_section_offset;
     size_t font_section_size;
 };
@@ -566,6 +589,14 @@ tablegen_sequences(const char *seq_font_tbl_out, const char *seq_order_path, con
     fprintf(out, ".balign 16\n");
 
     fclose(out);
+    free(final_seqdata);
+    for (int i = 0; i < num_sequence_files; i++) {
+        free(file_data[i].name);
+        free(file_data[i].elf_path);
+    }
+    free(file_data);
+    free_seq_order(&order);
+
     return EXIT_SUCCESS;
 }