Revert "Set SA_RESTORER in sigaction()"

This reverts commit e4fa46e75cd0d433b5c6c064720ed7e195cba7c8.
diff --git a/libc/arch-arm/syscalls/sigaction.S b/libc/arch-arm/syscalls/sigaction.S
new file mode 100644
index 0000000..2696f1e
--- /dev/null
+++ b/libc/arch-arm/syscalls/sigaction.S
@@ -0,0 +1,19 @@
+/* autogenerated by gensyscalls.py */
+#include <sys/linux-syscalls.h>
+
+    .text
+    .type sigaction, #function
+    .globl sigaction
+    .align 4
+    .fnstart
+
+sigaction:
+    .save   {r4, r7}
+    stmfd   sp!, {r4, r7}
+    ldr     r7, =__NR_sigaction
+    swi     #0
+    ldmfd   sp!, {r4, r7}
+    movs    r0, r0
+    bxpl    lr
+    b       __set_syscall_errno
+    .fnend