add sigaltstack syscall
diff --git a/libc/arch-arm/syscalls.mk b/libc/arch-arm/syscalls.mk
index 96471bf..3020930 100644
--- a/libc/arch-arm/syscalls.mk
+++ b/libc/arch-arm/syscalls.mk
@@ -37,6 +37,7 @@
syscall_src += arch-arm/syscalls/prctl.S
syscall_src += arch-arm/syscalls/capget.S
syscall_src += arch-arm/syscalls/capset.S
+syscall_src += arch-arm/syscalls/sigaltstack.S
syscall_src += arch-arm/syscalls/acct.S
syscall_src += arch-arm/syscalls/read.S
syscall_src += arch-arm/syscalls/write.S
diff --git a/libc/arch-arm/syscalls/sigaltstack.S b/libc/arch-arm/syscalls/sigaltstack.S
new file mode 100644
index 0000000..3625d0b
--- /dev/null
+++ b/libc/arch-arm/syscalls/sigaltstack.S
@@ -0,0 +1,19 @@
+/* autogenerated by gensyscalls.py */
+#include <sys/linux-syscalls.h>
+
+ .text
+ .type sigaltstack, #function
+ .globl sigaltstack
+ .align 4
+ .fnstart
+
+sigaltstack:
+ .save {r4, r7}
+ stmfd sp!, {r4, r7}
+ ldr r7, =__NR_sigaltstack
+ swi #0
+ ldmfd sp!, {r4, r7}
+ movs r0, r0
+ bxpl lr
+ b __set_syscall_errno
+ .fnend