SDL: Sync SDL3 wiki -> header (2e18c)

From 2e18cf8d096657be40ab301a523e2f10a2a10508 Mon Sep 17 00:00:00 2001
From: SDL Wiki Bot <[EMAIL REDACTED]>
Date: Sun, 22 Feb 2026 00:07:28 +0000
Subject: [PATCH] Sync SDL3 wiki -> header

[ci skip]
---
 include/SDL3/SDL_stdinc.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/SDL3/SDL_stdinc.h b/include/SDL3/SDL_stdinc.h
index d2bcb157fdd3e..205f9bc3b644e 100644
--- a/include/SDL3/SDL_stdinc.h
+++ b/include/SDL3/SDL_stdinc.h
@@ -1816,6 +1816,11 @@ extern SDL_DECLSPEC const char * SDLCALL SDL_getenv(const char *name);
  * This function bypasses SDL's cached copy of the environment and is not
  * thread-safe.
  *
+ * On some platforms, this may make case-insensitive matches, while other
+ * platforms are case-sensitive. It is best to be precise with strings used
+ * for queries through this interface. SDL_getenv is always case-sensitive,
+ * however.
+ *
  * \param name the name of the variable to get.
  * \returns a pointer to the value of the variable or NULL if it can't be
  *          found.