diff --git a/boards/sim/sim/sim/configs/cxxtest/Make.defs b/boards/sim/sim/sim/configs/cxxtest/Make.defs
index 53fe2d56dc4..47f169a7493 100644
--- a/boards/sim/sim/sim/configs/cxxtest/Make.defs
+++ b/boards/sim/sim/sim/configs/cxxtest/Make.defs
@@ -60,6 +60,11 @@ ARCHINCLUDES = -I. -isystem $(TOPDIR)/include
 ARCHINCLUDESXX = -I. -isystem $(TOPDIR)/include -isystem $(TOPDIR)/include/cxx -isystem $(TOPDIR)/include/uClibc++
 ARCHSCRIPT =
 
+# Add -fno-common because macOS "ld -r" doesn't seem to pick objects
+# for common symbols.
+ARCHCPUFLAGS += -fno-common
+ARCHCPUFLAGSXX += -fno-common
+
 ifeq ($(CONFIG_SIM_M32),y)
   ARCHCPUFLAGS += -m32
   ARCHCPUFLAGSXX += -m32
diff --git a/boards/sim/sim/sim/configs/nsh2/Make.defs b/boards/sim/sim/sim/configs/nsh2/Make.defs
index b00ada0bfbc..680efd6df75 100644
--- a/boards/sim/sim/sim/configs/nsh2/Make.defs
+++ b/boards/sim/sim/sim/configs/nsh2/Make.defs
@@ -57,6 +57,11 @@ ARCHINCLUDES		= -I. -isystem $(TOPDIR)/include
 ARCHINCLUDESXX		= -I. -isystem $(TOPDIR)/include -isystem $(TOPDIR)/include/cxx
 ARCHSCRIPT		=
 
+# Add -fno-common because macOS "ld -r" doesn't seem to pick objects
+# for common symbols.
+ARCHCPUFLAGS += -fno-common
+ARCHCPUFLAGSXX += -fno-common
+
 ifeq ($(CONFIG_SIM_M32),y)
   ARCHCPUFLAGS		+= -m32
   ARCHCPUFLAGSXX	+= -m32
diff --git a/boards/sim/sim/sim/scripts/Make.defs b/boards/sim/sim/sim/scripts/Make.defs
index 9eb3d13c2ea..b1fca660d4d 100644
--- a/boards/sim/sim/sim/scripts/Make.defs
+++ b/boards/sim/sim/sim/scripts/Make.defs
@@ -63,6 +63,11 @@ ARCHINCLUDES = -I. -isystem $(TOPDIR)/include
 ARCHINCLUDESXX = -I. -isystem $(TOPDIR)/include -isystem $(TOPDIR)/include/cxx
 ARCHSCRIPT =
 
+# Add -fno-common because macOS "ld -r" doesn't seem to pick objects
+# for common symbols.
+ARCHCPUFLAGS += -fno-common
+ARCHCPUFLAGSXX += -fno-common
+
 ifeq ($(CONFIG_SIM_M32),y)
   ARCHCPUFLAGS += -m32
   ARCHCPUFLAGSXX += -m32