Fix PFLINK mechanism for uppercase float conversion specifiers (#796)

_PFLINK is supposed to automatically pull in required functions for
specific conversion specifiers. However, it fails to do so for the F,
G and E conversion specifiers.

This means that, for example, the following program:

 #include <stdio.h>

int main()
{
    printf("%F %G %E\n", .0, .0, .0);
}

fails to run correctly, printing "? ? ?" instead of
"0.000000 0 0.000000E+00".

This patch fixes this.

libc/fmt/pflink.h

@@ -14,7 +14,7 @@
 #define PFLINK(...) _PFLINK(__VA_ARGS__)
 #define _PFLINK(FMT, ...)                                                \
   ({                                                                     \
-    if (___PFLINK(FMT, strpbrk, "faAeg")) STATIC_YOINK("__fmt_dtoa"); \
+    if (___PFLINK(FMT, strpbrk, "fFaAeEgG")) STATIC_YOINK("__fmt_dtoa"); \
     if (___PFLINK(FMT, strpbrk, "cmrqs")) {                              \
       if (___PFLINK(FMT, strstr, "%m")) STATIC_YOINK("strerror");        \
       if (___PFLINK(FMT, strstr, "%*") ||                                \

test/libc/fmt/printf_uppercase_e_static_yoink_test.c

@@ -0,0 +1,42 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Gabriel Ravier                                                │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+
+#include "libc/fmt/fmt.h"
+#include "libc/intrin/kprintf.h"
+#include "libc/runtime/runtime.h"
+#include "libc/str/str.h"
+
+// We specifically avoid the test framework because otherwise __fmt_dtoa is
+// always automatically pulled in from code in there - and this is what we're
+// testing for here
+int main() {
+  char buffer[30];
+
+  int snprintf_result = snprintf(buffer, sizeof(buffer), "%E", .0);
+  if (strcmp(buffer, "0.000000E+00")) {
+    kprintf(
+        "error: snprintf gave us '%s' instead of the expected '0.000000E+00'\n",
+        buffer);
+    abort();
+  }
+  if (snprintf_result != 12) {
+    kprintf("error: snprintf returned %d instead of 12\n", snprintf_result);
+    abort();
+  }
+}

test/libc/fmt/printf_uppercase_f_static_yoink_test.c

@@ -0,0 +1,41 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Gabriel Ravier                                                │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+
+#include "libc/fmt/fmt.h"
+#include "libc/intrin/kprintf.h"
+#include "libc/runtime/runtime.h"
+#include "libc/str/str.h"
+
+// We specifically avoid the test framework because otherwise __fmt_dtoa is
+// always automatically pulled in from code in there - and this is what we're
+// testing for here
+int main() {
+  char buffer[30];
+
+  int snprintf_result = snprintf(buffer, sizeof(buffer), "%F", .0);
+  if (strcmp(buffer, "0.000000")) {
+    kprintf("error: snprintf gave us '%s' instead of the expected '0.000000'\n",
+            buffer);
+    abort();
+  }
+  if (snprintf_result != 8) {
+    kprintf("error: snprintf returned %d instead of 8\n", snprintf_result);
+    abort();
+  }
+}

test/libc/fmt/printf_uppercase_g_static_yoink_test.c

@@ -0,0 +1,41 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Gabriel Ravier                                                │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+
+#include "libc/fmt/fmt.h"
+#include "libc/intrin/kprintf.h"
+#include "libc/runtime/runtime.h"
+#include "libc/str/str.h"
+
+// We specifically avoid the test framework because otherwise __fmt_dtoa is
+// always automatically pulled in from code in there - and this is what we're
+// testing for here
+int main() {
+  char buffer[30];
+
+  int snprintf_result = snprintf(buffer, sizeof(buffer), "%G", .0);
+  if (strcmp(buffer, "0")) {
+    kprintf("error: snprintf gave us '%s' instead of the expected '0'\n",
+            buffer);
+    abort();
+  }
+  if (snprintf_result != 1) {
+    kprintf("error: snprintf returned %d instead of 1\n", snprintf_result);
+    abort();
+  }
+}