diff --git a/extras/Makefile.am b/extras/Makefile.am
index 59b02924..1bd72203 100644
--- a/extras/Makefile.am
+++ b/extras/Makefile.am
@@ -8,6 +8,7 @@ libwebpextras_la_SOURCES =
 libwebpextras_la_SOURCES += extras.c extras.h quality_estimate.c
 
 libwebpextras_la_CPPFLAGS = $(AM_CPPFLAGS)
+libwebpextras_la_LDFLAGS = -lm
 libwebpextras_la_LIBADD = ../src/libwebp.la
 
 noinst_PROGRAMS = get_disto webp_quality
diff --git a/src/mux/Makefile.am b/src/mux/Makefile.am
index 042a14ba..85882c89 100644
--- a/src/mux/Makefile.am
+++ b/src/mux/Makefile.am
@@ -13,6 +13,6 @@ libwebpmuxinclude_HEADERS += ../webp/mux_types.h
 libwebpmuxinclude_HEADERS += ../webp/types.h
 
 libwebpmux_la_LIBADD = ../libwebp.la
-libwebpmux_la_LDFLAGS = -no-undefined -version-info 2:1:0
+libwebpmux_la_LDFLAGS = -no-undefined -version-info 2:1:0 -lm
 libwebpmuxincludedir = $(includedir)/webp
 pkgconfig_DATA = libwebpmux.pc
diff --git a/src/mux/libwebpmux.pc.in b/src/mux/libwebpmux.pc.in
index 8f87dfe5..a96fac78 100644
--- a/src/mux/libwebpmux.pc.in
+++ b/src/mux/libwebpmux.pc.in
@@ -9,3 +9,4 @@ Version: @PACKAGE_VERSION@
 Requires: libwebp >= 0.2.0
 Cflags: -I${includedir}
 Libs: -L${libdir} -lwebpmux
+Libs.private: -lm