--- /dev/null
+From: Lukas Schwaighofer <lukas@schwaighofer.name>
+Date: Tue, 26 Feb 2019 23:13:58 +0100
+Subject: Prevent optimizing the pow() function
+
+With the current GCC 8.2.0 from Debian, a section of code calling pow() in
+zzjson_parse.c is turned into a sequence calling exp(). Since no exp()
+implementation is available in syslinux those optimizations need to be
+disabled.
+---
+ com32/gpllib/zzjson/zzjson_parse.c | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/com32/gpllib/zzjson/zzjson_parse.c b/com32/gpllib/zzjson/zzjson_parse.c
+index ecb6f61..e66a9d8 100644
+--- a/com32/gpllib/zzjson/zzjson_parse.c
++++ b/com32/gpllib/zzjson/zzjson_parse.c
+@@ -138,6 +138,10 @@ static ZZJSON *parse_string2(ZZJSON_CONFIG *config) {
+ return zzjson;
+ }
+
++static double __attribute__((optimize("O0"))) pow_noopt(double x, double y) {
++ return pow(x, y);
++}
++
+ static ZZJSON *parse_number(ZZJSON_CONFIG *config) {
+ ZZJSON *zzjson;
+ unsigned long long ival = 0, expo = 0;
+@@ -213,7 +217,7 @@ skipexpo:
+ if (dbl) {
+ dval = sign * (long long) ival;
+ dval += sign * frac;
+- dval *= pow(10.0, (double) signexpo * expo);
++ dval *= pow_noopt(10.0, (double) signexpo * expo);
+ }
+
+ zzjson = config->calloc(1, sizeof(ZZJSON));
--- /dev/null
+--- a/mk/com32.mk
++++ b/mk/com32.mk
+@@ -47,6 +47,7 @@ GCCOPT += $(call gcc_ok,-falign-functions=0,-malign-functions=0)
+ GCCOPT += $(call gcc_ok,-falign-jumps=0,-malign-jumps=0)
+ GCCOPT += $(call gcc_ok,-falign-labels=0,-malign-labels=0)
+ GCCOPT += $(call gcc_ok,-falign-loops=0,-malign-loops=0)
++GCCOPT += $(call gcc_ok,-fcommon)
+
+ ifeq ($(FWCLASS),EFI)
+ GCCOPT += -mno-red-zone
+--- a/mk/elf.mk
++++ b/mk/elf.mk
+@@ -42,6 +42,7 @@ GCCOPT += $(call gcc_ok,-falign-functions=0,-malign-functions=0)
+ GCCOPT += $(call gcc_ok,-falign-jumps=0,-malign-jumps=0)
+ GCCOPT += $(call gcc_ok,-falign-labels=0,-malign-labels=0)
+ GCCOPT += $(call gcc_ok,-falign-loops=0,-malign-loops=0)
++GCCOPT += $(call gcc_ok,-fcommon)
+
+ com32 = $(topdir)/com32
+ core = $(topdir)/core
+--- a/mk/embedded.mk
++++ b/mk/embedded.mk
+@@ -51,6 +51,7 @@ GCCOPT += $(call gcc_ok,-falign-jumps=0,-malign-jumps=0)
+ GCCOPT += $(call gcc_ok,-falign-labels=0,-malign-labels=0)
+ GCCOPT += $(call gcc_ok,-falign-loops=0,-malign-loops=0)
+ GCCOPT += $(call gcc_ok,-fvisibility=hidden)
++GCCOPT += $(call gcc_ok,-fcommon)
+
+ LIBGCC := $(shell $(CC) $(GCCOPT) --print-libgcc)
+
+--- a/mk/lib.mk
++++ b/mk/lib.mk
+@@ -28,6 +28,7 @@ GCCOPT += $(call gcc_ok,-falign-functions=0,-malign-functions=0)
+ GCCOPT += $(call gcc_ok,-falign-jumps=0,-malign-jumps=0)
+ GCCOPT += $(call gcc_ok,-falign-labels=0,-malign-labels=0)
+ GCCOPT += $(call gcc_ok,-falign-loops=0,-malign-loops=0)
++GCCOPT += $(call gcc_ok,-fcommon)
+
+ INCLUDE = -I$(SRC)
+ STRIP = strip --strip-all -R .comment -R .note
+--- a/mk/efi.mk
++++ b/mk/efi.mk
+@@ -7,7 +7,7 @@ core = $(topdir)/core
+ # Set up architecture specifics; for cross compilation, set ARCH as apt
+ # gnuefi sets up architecture specifics in ia32 or x86_64 sub directories
+ # set up the LIBDIR and EFIINC for building for the appropriate architecture
+-GCCOPT := $(call gcc_ok,-fno-stack-protector,)
++GCCOPT := $(call gcc_ok,-fno-stack-protector,) $(call gcc_ok,-fcommon)
+ EFIINC = $(objdir)/include/efi
+ LIBDIR = $(objdir)/lib