[git commit branch/1_27_stable] tls: fix build problem on non-static i386

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=25f07f589844063307f488b2d07d27e3681285a5
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/1_27_stable

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 networking/tls.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/networking/tls.h b/networking/tls.h
index d487f38..b80cc64 100644
--- a/networking/tls.h
+++ b/networking/tls.h
@@ -26,8 +26,10 @@
 #undef  USE_SEED
 /* pstm: multiprecision numbers */
 #undef  DISABLE_PSTM
-#if defined(__GNUC__) && defined(__i386__)
+#if defined(__GNUC__) && defined(__i386__) && ENABLE_STATIC
   /* PSTM_X86 works correctly. +25 bytes. */
+  /* Only enabled on static build since tls_pstm_mul_comba.c::MULADD
+   * and tls_pstm_sqr_comba.c::SQRADD2 need too many registers, choke when ebx is not available */
 # define PSTM_32BIT
 # define PSTM_X86
 #endif