firefox: remove obsolete patch

srcpkgs/firefox/patches/fix-i386-fdlibm.patch

@@ -1,18 +0,0 @@
-# error: typedef redefinition with different types ('__double_t' (aka 'double') vs 'long double')
-# https://bugzilla.mozilla.org/show_bug.cgi?id=1729459
-
---- a/modules/fdlibm/src/math_private.h
-+++ b/modules/fdlibm/src/math_private.h
-@@ -30,7 +30,12 @@
-  * Adapted from https://github.com/freebsd/freebsd-src/search?q=__double_t
-  */
- 
-+#if defined(__linux__) && defined(__i386__)
-+// rely on glibc's double_t
-+typedef long double __double_t;
-+#else
- typedef double      __double_t;
-+#endif
- typedef __double_t  double_t;
- 
- /*