Add missing SHT_LOOS/SHT_HIOS values

Change-Id: Ib0b0987a7e85af7863c6ef894263b5980e32344d
diff --git a/libc/include/elf.h b/libc/include/elf.h
index 2039cc0..a41a244 100644
--- a/libc/include/elf.h
+++ b/libc/include/elf.h
@@ -106,6 +106,9 @@
 #define STB_LOPROC    13
 #define STB_HIPROC    15
 
+#define SHT_LOOS    0x60000000
+#define SHT_HIOS    0x6fffffff
+
 #define STT_GNU_IFUNC 10
 #define STT_LOOS      10
 #define STT_HIOS      12