diff --git a/.travis.yml b/.travis.yml
index 7c926b2..b04f55a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -81,12 +81,12 @@ install:
 script:
 
     # Download and build libbitcoin-client and all dependencies.
-    - if [[ $OSX   && $CLANG && $STATIC  ]]; then CC=$CC CXX=$CXX ./install.sh --disable-shared --build-boost --build-zmq --prefix=$TRAVIS_BUILD_DIR/my-prefix; fi
-    - if [[ $LINUX && $CLANG && $STATIC  ]]; then CC=$CC CXX=$CXX ./install.sh --disable-shared --build-boost --build-zmq --prefix=$TRAVIS_BUILD_DIR/my-prefix CFLAGS='-Os' CXXFLAGS='-Os'; fi
-    - if [[ $LINUX && $GCC   && $STATIC  ]]; then CC=$CC CXX=$CXX ./install.sh --build-boost --build-zmq --disable-shared --build-dir=my-build --prefix=$TRAVIS_BUILD_DIR/my-prefix CFLAGS='-Og -g --coverage' CXXFLAGS='-Og -g --coverage'; fi
-    - if [[ $OSX   && $CLANG && $DYNAMIC ]]; then CC=$CC CXX=$CXX ./install.sh --disable-static --build-zmq; fi
-    - if [[ $LINUX && $CLANG && $DYNAMIC ]]; then CC=$CC CXX=$CXX ./install.sh --build-boost --build-zmq --disable-ndebug --disable-static --prefix=$TRAVIS_BUILD_DIR/my-prefix CFLAGS='-Os' CXXFLAGS='-Os'; fi
-    - if [[ $LINUX && $GCC   && $DYNAMIC ]]; then CC=$CC CXX=$CXX ./install.sh --disable-static --build-boost --build-zmq --prefix=$TRAVIS_BUILD_DIR/my-prefix CFLAGS='-Os -s' CXXFLAGS='-Os -s'; fi
+    - if [[ $OSX   && $CLANG && $STATIC  ]]; then CC=$CC CXX=$CXX ./install.sh --enable-isystem --disable-shared --build-boost --build-zmq --prefix=$TRAVIS_BUILD_DIR/my-prefix; fi
+    - if [[ $LINUX && $CLANG && $STATIC  ]]; then CC=$CC CXX=$CXX ./install.sh --enable-isystem --disable-shared --build-boost --build-zmq --prefix=$TRAVIS_BUILD_DIR/my-prefix CFLAGS='-Os' CXXFLAGS='-Os'; fi
+    - if [[ $LINUX && $GCC   && $STATIC  ]]; then CC=$CC CXX=$CXX ./install.sh --enable-isystem --build-boost --build-zmq --disable-shared --build-dir=my-build --prefix=$TRAVIS_BUILD_DIR/my-prefix CFLAGS='-Og -g --coverage' CXXFLAGS='-Og -g --coverage'; fi
+    - if [[ $OSX   && $CLANG && $DYNAMIC ]]; then CC=$CC CXX=$CXX ./install.sh --enable-isystem --disable-static --build-zmq; fi
+    - if [[ $LINUX && $CLANG && $DYNAMIC ]]; then CC=$CC CXX=$CXX ./install.sh --enable-isystem --build-boost --build-zmq --disable-ndebug --disable-static --prefix=$TRAVIS_BUILD_DIR/my-prefix CFLAGS='-Os' CXXFLAGS='-Os'; fi
+    - if [[ $LINUX && $GCC   && $DYNAMIC ]]; then CC=$CC CXX=$CXX ./install.sh --enable-isystem --disable-static --build-boost --build-zmq --prefix=$TRAVIS_BUILD_DIR/my-prefix CFLAGS='-Os -s' CXXFLAGS='-Os -s'; fi
 
 after_success:
 
diff --git a/Makefile.am b/Makefile.am
index 4025826..9e6404d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -32,7 +32,7 @@ doc_DATA = \
 # src/libbitcoin-client.la => ${libdir}
 #------------------------------------------------------------------------------
 lib_LTLIBRARIES = src/libbitcoin-client.la
-src_libbitcoin_client_la_CPPFLAGS = -I${srcdir}/include ${bitcoin_CPPFLAGS} ${bitcoin_protocol_CPPFLAGS}
+src_libbitcoin_client_la_CPPFLAGS = -I${srcdir}/include ${bitcoin_BUILD_CPPFLAGS} ${bitcoin_protocol_BUILD_CPPFLAGS}
 src_libbitcoin_client_la_LIBADD = ${bitcoin_LIBS} ${bitcoin_protocol_LIBS}
 src_libbitcoin_client_la_SOURCES = \
     src/dealer.cpp \
@@ -47,7 +47,7 @@ if WITH_TESTS
 TESTS = libbitcoin-client-test_runner.sh
 
 check_PROGRAMS = test/libbitcoin-client-test
-test_libbitcoin_client_test_CPPFLAGS = -I${srcdir}/include ${bitcoin_CPPFLAGS} ${bitcoin_protocol_CPPFLAGS}
+test_libbitcoin_client_test_CPPFLAGS = -I${srcdir}/include ${bitcoin_BUILD_CPPFLAGS} ${bitcoin_protocol_BUILD_CPPFLAGS}
 test_libbitcoin_client_test_LDADD = src/libbitcoin-client.la ${boost_unit_test_framework_LIBS} ${bitcoin_LIBS} ${bitcoin_protocol_LIBS}
 test_libbitcoin_client_test_SOURCES = \
     test/main.cpp \
@@ -60,7 +60,7 @@ endif WITH_TESTS
 if WITH_EXAMPLES
 
 noinst_PROGRAMS = examples/console/console
-examples_console_console_CPPFLAGS = -I${srcdir}/include ${bitcoin_CPPFLAGS} ${bitcoin_protocol_CPPFLAGS}
+examples_console_console_CPPFLAGS = -I${srcdir}/include ${bitcoin_BUILD_CPPFLAGS} ${bitcoin_protocol_BUILD_CPPFLAGS}
 examples_console_console_LDADD = src/libbitcoin-client.la ${bitcoin_LIBS} ${bitcoin_protocol_LIBS}
 examples_console_console_SOURCES = \
     examples/console/client.cpp \
@@ -78,7 +78,7 @@ endif WITH_EXAMPLES
 if WITH_EXAMPLES
 
 noinst_PROGRAMS += examples/get_height/get_height
-examples_get_height_get_height_CPPFLAGS = -I${srcdir}/include ${bitcoin_CPPFLAGS} ${bitcoin_protocol_CPPFLAGS}
+examples_get_height_get_height_CPPFLAGS = -I${srcdir}/include ${bitcoin_BUILD_CPPFLAGS} ${bitcoin_protocol_BUILD_CPPFLAGS}
 examples_get_height_get_height_LDADD = src/libbitcoin-client.la ${bitcoin_LIBS} ${bitcoin_protocol_LIBS}
 examples_get_height_get_height_SOURCES = \
     examples/get_height/main.cpp
diff --git a/configure.ac b/configure.ac
index 8750877..abc1a85 100644
--- a/configure.ac
+++ b/configure.ac
@@ -44,6 +44,9 @@ AC_PROG_CXX
 # Enable shared libraries if available, and static if they don't conflict.
 AC_PROG_LIBTOOL
 
+# Enable sed for substitution.
+AC_PROG_SED
+
 # Compute the canonical host-system type variable host, including host_os.
 AC_CANONICAL_HOST
 
@@ -52,6 +55,9 @@ m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
 # Check for pkg-config.
 PKG_PROG_PKG_CONFIG
+AS_IF([test -n "$PKG_CONFIG"], [],
+    [AC_MSG_ERROR([pkg-config is required but was not found.])])
+
 
 # Declare environment variables that affect the build.
 #------------------------------------------------------------------------------
@@ -114,6 +120,16 @@ AS_CASE([${enable_ndebug}], [yes], AC_DEFINE([NDEBUG]))
 #------------------------------------------------------------------------------
 AS_CASE([${enable_shared}], [yes], AC_DEFINE([BOOST_ALL_DYN_LINK]))
 
+# Implement --enable-isystem.
+#------------------------------------------------------------------------------
+AC_MSG_CHECKING([--enable-isystem option])
+AC_ARG_ENABLE([isystem],
+    AS_HELP_STRING([--enable-isystem],
+        [Substitute -isystem for -I in dependencies. @<:@default=no@:>@]),
+    [enable_isystem=$enableval],
+    [enable_isystem=no])
+AC_MSG_RESULT([$enable_isystem])
+
 
 # Check dependencies.
 #==============================================================================
@@ -122,11 +138,19 @@ AS_CASE([${enable_shared}], [yes], AC_DEFINE([BOOST_ALL_DYN_LINK]))
 AS_CASE([${CC}], [*],
     [AX_BOOST_BASE([1.62.0],
         [AC_SUBST([boost_CPPFLAGS], [${BOOST_CPPFLAGS}])
+         AC_SUBST([boost_ISYS_CPPFLAGS], [`echo ${BOOST_CPPFLAGS} | $SED s/^-I/-isystem/g | $SED s/' -I'/' -isystem'/g`])
          AC_SUBST([boost_LDFLAGS], [${BOOST_LDFLAGS}])
          AC_MSG_NOTICE([boost_CPPFLAGS : ${boost_CPPFLAGS}])
+         AC_MSG_NOTICE([boost_ISYS_CPPFLAGS : ${boost_ISYS_CPPFLAGS}])
          AC_MSG_NOTICE([boost_LDFLAGS : ${boost_LDFLAGS}])],
         [AC_MSG_ERROR([Boost 1.62.0 or later is required but was not found.])])])
 
+AS_CASE([${enable_isystem}],[yes],
+    [AC_SUBST([boost_BUILD_CPPFLAGS], [${boost_ISYS_CPPFLAGS}])],
+    [AC_SUBST([boost_BUILD_CPPFLAGS], [${boost_CPPFLAGS}])])
+
+AC_MSG_NOTICE([boost_BUILD_CPPFLAGS : ${boost_BUILD_CPPFLAGS}])
+
 AS_CASE([${with_tests}], [yes],
     [AX_BOOST_UNIT_TEST_FRAMEWORK
      AC_SUBST([boost_unit_test_framework_LIBS], [${BOOST_UNIT_TEST_FRAMEWORK_LIB}])
@@ -135,20 +159,52 @@ AS_CASE([${with_tests}], [yes],
 
 # Require bitcoin of at least version 4.0.0 and output ${bitcoin_CPPFLAGS/LIBS/PKG}.
 #------------------------------------------------------------------------------
-PKG_CHECK_MODULES([bitcoin], [libbitcoin >= 4.0.0])
+PKG_CHECK_MODULES([bitcoin], [libbitcoin >= 4.0.0],
+    [bitcoin_INCLUDEDIR="`$PKG_CONFIG --variable=includedir "libbitcoin >= 4.0.0" 2>/dev/null`"
+     bitcoin_OTHER_CFLAGS="`$PKG_CONFIG --cflags-only-other "libbitcoin >= 4.0.0" 2>/dev/null`"],
+    [bitcoin_INCLUDEDIR=""
+     bitcoin_OTHER_CFLAGS=""])
 AC_SUBST([bitcoin_PKG], ['libbitcoin >= 4.0.0'])
 AC_SUBST([bitcoin_CPPFLAGS], [${bitcoin_CFLAGS}])
+AS_IF([test x${bitcoin_INCLUDEDIR} != "x"],
+    [AC_SUBST([bitcoin_ISYS_CPPFLAGS], ["-isystem${bitcoin_INCLUDEDIR} ${bitcoin_OTHER_CFLAGS}"])],
+    [AC_SUBST([bitcoin_ISYS_CPPFLAGS], [${bitcoin_OTHER_CFLAGS}])])
 AC_MSG_NOTICE([bitcoin_CPPFLAGS : ${bitcoin_CPPFLAGS}])
+AC_MSG_NOTICE([bitcoin_ISYS_CPPFLAGS : ${bitcoin_ISYS_CPPFLAGS}])
+AC_MSG_NOTICE([bitcoin_OTHER_CFLAGS : ${bitcoin_OTHER_CFLAGS}])
+AC_MSG_NOTICE([bitcoin_INCLUDEDIR : ${bitcoin_INCLUDEDIR}])
 AC_MSG_NOTICE([bitcoin_LIBS : ${bitcoin_LIBS}])
 
+AS_CASE([${enable_isystem}],[yes],
+    [AC_SUBST([bitcoin_BUILD_CPPFLAGS], [${bitcoin_ISYS_CPPFLAGS}])],
+    [AC_SUBST([bitcoin_BUILD_CPPFLAGS], [${bitcoin_CPPFLAGS}])])
+
+AC_MSG_NOTICE([bitcoin_BUILD_CPPFLAGS : ${bitcoin_BUILD_CPPFLAGS}])
+
 # Require bitcoin-protocol of at least version 4.0.0 and output ${bitcoin_protocol_CPPFLAGS/LIBS/PKG}.
 #------------------------------------------------------------------------------
-PKG_CHECK_MODULES([bitcoin_protocol], [libbitcoin-protocol >= 4.0.0])
+PKG_CHECK_MODULES([bitcoin_protocol], [libbitcoin-protocol >= 4.0.0],
+    [bitcoin_protocol_INCLUDEDIR="`$PKG_CONFIG --variable=includedir "libbitcoin-protocol >= 4.0.0" 2>/dev/null`"
+     bitcoin_protocol_OTHER_CFLAGS="`$PKG_CONFIG --cflags-only-other "libbitcoin-protocol >= 4.0.0" 2>/dev/null`"],
+    [bitcoin_protocol_INCLUDEDIR=""
+     bitcoin_protocol_OTHER_CFLAGS=""])
 AC_SUBST([bitcoin_protocol_PKG], ['libbitcoin-protocol >= 4.0.0'])
 AC_SUBST([bitcoin_protocol_CPPFLAGS], [${bitcoin_protocol_CFLAGS}])
+AS_IF([test x${bitcoin_protocol_INCLUDEDIR} != "x"],
+    [AC_SUBST([bitcoin_protocol_ISYS_CPPFLAGS], ["-isystem${bitcoin_protocol_INCLUDEDIR} ${bitcoin_protocol_OTHER_CFLAGS}"])],
+    [AC_SUBST([bitcoin_protocol_ISYS_CPPFLAGS], [${bitcoin_protocol_OTHER_CFLAGS}])])
 AC_MSG_NOTICE([bitcoin_protocol_CPPFLAGS : ${bitcoin_protocol_CPPFLAGS}])
+AC_MSG_NOTICE([bitcoin_protocol_ISYS_CPPFLAGS : ${bitcoin_protocol_ISYS_CPPFLAGS}])
+AC_MSG_NOTICE([bitcoin_protocol_OTHER_CFLAGS : ${bitcoin_protocol_OTHER_CFLAGS}])
+AC_MSG_NOTICE([bitcoin_protocol_INCLUDEDIR : ${bitcoin_protocol_INCLUDEDIR}])
 AC_MSG_NOTICE([bitcoin_protocol_LIBS : ${bitcoin_protocol_LIBS}])
 
+AS_CASE([${enable_isystem}],[yes],
+    [AC_SUBST([bitcoin_protocol_BUILD_CPPFLAGS], [${bitcoin_protocol_ISYS_CPPFLAGS}])],
+    [AC_SUBST([bitcoin_protocol_BUILD_CPPFLAGS], [${bitcoin_protocol_CPPFLAGS}])])
+
+AC_MSG_NOTICE([bitcoin_protocol_BUILD_CPPFLAGS : ${bitcoin_protocol_BUILD_CPPFLAGS}])
+
 
 # Set flags.
 #==============================================================================
@@ -164,12 +220,24 @@ AS_CASE([${CC}], [*],
     [AX_CHECK_COMPILE_FLAG([-Wall],
         [CFLAGS="$CFLAGS -Wall"])])
 
+# Warn on all stuff.
+#------------------------------------------------------------------------------
+AS_CASE([${CC}], [*],
+    [AX_CHECK_COMPILE_FLAG([-Wall],
+        [CXXFLAGS="$CXXFLAGS -Wall"])])
+
 # Warn on extra stuff.
 #------------------------------------------------------------------------------
 AS_CASE([${CC}], [*],
     [AX_CHECK_COMPILE_FLAG([-Wextra],
         [CFLAGS="$CFLAGS -Wextra"])])
 
+# Warn on extra stuff.
+#------------------------------------------------------------------------------
+AS_CASE([${CC}], [*],
+    [AX_CHECK_COMPILE_FLAG([-Wextra],
+        [CXXFLAGS="$CXXFLAGS -Wextra"])])
+
 # Be really annoying.
 #------------------------------------------------------------------------------
 AS_CASE([${CC}], [*],
@@ -178,6 +246,26 @@ AS_CASE([${CC}], [*],
         [AX_CHECK_COMPILE_FLAG([-pedantic],
             [CFLAGS="$CFLAGS -pedantic"])])])
 
+# Be really annoying.
+#------------------------------------------------------------------------------
+AS_CASE([${CC}], [*],
+    [AX_CHECK_COMPILE_FLAG([-Wpedantic],
+        [CXXFLAGS="$CXXFLAGS -Wpedantic"],
+        [AX_CHECK_COMPILE_FLAG([-pedantic],
+            [CXXFLAGS="$CXXFLAGS -pedantic"])])])
+
+# Disallow warning on style order of declarations.
+#------------------------------------------------------------------------------
+AS_CASE([${CC}], [*],
+    [AX_CHECK_COMPILE_FLAG([-Wno-reorder],
+        [CXXFLAGS="$CXXFLAGS -Wno-reorder"])])
+
+# Suppress warning for incomplete field initialization.
+#------------------------------------------------------------------------------
+AS_CASE([${CC}], [*],
+    [AX_CHECK_COMPILE_FLAG([-Wno-missing-field-initializers],
+        [CXXFLAGS="$CXXFLAGS -Wno-missing-field-initializers"])])
+
 # Conform to style.
 #------------------------------------------------------------------------------
 AS_CASE([${CC}], [*],
@@ -190,12 +278,6 @@ AS_CASE([${CC}], [*clang*],
     [AX_CHECK_COMPILE_FLAG([-Wno-mismatched-tags],
         [CXXFLAGS="$CXXFLAGS -Wno-mismatched-tags"])])
 
-# Clean up boost 1.55 headers. Enabled in gcc only.
-#------------------------------------------------------------------------------
-AS_CASE([${CC}], [*gcc*],
-    [AX_CHECK_COMPILE_FLAG([-Wno-deprecated-declarations],
-        [CXXFLAGS="$CXXFLAGS -Wno-deprecated-declarations"])])
-
 # Protect stack.
 #------------------------------------------------------------------------------
 AS_CASE([${CC}], [*],
@@ -208,12 +290,6 @@ AS_CASE([${CC}], [*],
     [AX_CHECK_LINK_FLAG([-fstack-protector-all],
         [LDFLAGS="$LDFLAGS -fstack-protector-all"])])
 
-# Hide internal functions from external libs. Enabled in gcc only.
-#------------------------------------------------------------------------------
-AS_CASE([${CC}], [*gcc*],
-    [AX_CHECK_COMPILE_FLAG([-fvisibility-hidden],
-        [CXXFLAGS="$CXXFLAGS -fvisibility-hidden"])])
-
 # Hide inlines from external libs. Enabled in gcc only.
 #------------------------------------------------------------------------------
 AS_CASE([${CC}], [*gcc*],
diff --git a/src/dealer.cpp b/src/dealer.cpp
index 66d99f4..c4f0c05 100644
--- a/src/dealer.cpp
+++ b/src/dealer.cpp
@@ -185,7 +185,7 @@ bool dealer::send(const obelisk_message& message)
 }
 
 // Stream interface, not utilized on this class.
-bool dealer::read(stream& stream)
+bool dealer::read(stream& )
 {
     return false;
 }
diff --git a/src/obelisk_client.cpp b/src/obelisk_client.cpp
index d832800..6477fa3 100644
--- a/src/obelisk_client.cpp
+++ b/src/obelisk_client.cpp
@@ -35,7 +35,7 @@ static uint32_t to_milliseconds(uint16_t seconds)
 {
     const auto milliseconds = static_cast<uint32_t>(seconds) * 1000;
     return std::min(milliseconds, max_uint32);
-};
+}
 
 static const auto on_unknown = [](const std::string&){};
 
diff --git a/test/proxy.cpp b/test/proxy.cpp
index d945a0f..9f3b122 100644
--- a/test/proxy.cpp
+++ b/test/proxy.cpp
@@ -38,7 +38,7 @@ class stream_fixture
         return 0;
     }
 
-    virtual bool read(stream& stream) override
+    virtual bool read(stream& ) override
     {
         return false;
     }