Change ARG_MAX/_SC_ARG_MAX back to a constant.

As per the lkml thread https://lkml.org/lkml/2017/11/1/946.

Bug: http://b/65818597
Test: ran tests
Change-Id: I7a0610e6903e6761f2b31416e2f5017bd7a60659
diff --git a/libc/kernel/tools/defaults.py b/libc/kernel/tools/defaults.py
index b0fb95f..586cb02 100644
--- a/libc/kernel/tools/defaults.py
+++ b/libc/kernel/tools/defaults.py
@@ -58,8 +58,6 @@
 
 # Replace tokens in the output according to this mapping.
 kernel_token_replacements = {
-    # The kernel's ARG_MAX is actually the "minimum" maximum (see fs/exec.c).
-    "ARG_MAX": "_KERNEL_ARG_MAX",
     # The kernel usage of __unused for unused struct fields conflicts with the macro defined in <sys/cdefs.h>.
     "__unused": "__linux_unused",
     # The kernel usage of C++ keywords causes problems for C++ code so rename.
diff --git a/libc/kernel/uapi/linux/limits.h b/libc/kernel/uapi/linux/limits.h
index 41108f9..ad0e33e 100644
--- a/libc/kernel/uapi/linux/limits.h
+++ b/libc/kernel/uapi/linux/limits.h
@@ -20,7 +20,7 @@
 #define _LINUX_LIMITS_H
 #define NR_OPEN 1024
 #define NGROUPS_MAX 65536
-#define _KERNEL_ARG_MAX 131072
+#define ARG_MAX 131072
 #define LINK_MAX 127
 #define MAX_CANON 255
 #define MAX_INPUT 255