diff --git a/builds/install/arch-specific/linux/linuxLibrary.sh.in b/builds/install/arch-specific/linux/linuxLibrary.sh.in
index f5217ebf9a..f1fe91e7d7 100644
--- a/builds/install/arch-specific/linux/linuxLibrary.sh.in
+++ b/builds/install/arch-specific/linux/linuxLibrary.sh.in
@@ -573,3 +573,10 @@ haveLibrary() {
 	return $?
 }
 
+
+#------------------------------------------------------------------------
+# refresh cache of dynamic loader after add/delete files in system libdir
+
+reconfigDynamicLoader() {
+	ldconfig
+}
diff --git a/builds/install/arch-specific/linux/makeInstallImage.sh.in b/builds/install/arch-specific/linux/makeInstallImage.sh.in
index 028aab726d..45baa9689e 100644
--- a/builds/install/arch-specific/linux/makeInstallImage.sh.in
+++ b/builds/install/arch-specific/linux/makeInstallImage.sh.in
@@ -33,6 +33,7 @@ BuildRootDir=..
 BuiltFBDir=Release/firebird  # Where the just build fb exists.
 TargetDir=buildroot    # Where we want to build the install image
 SecurityDatabase=security4.fdb
+TomBuild="@TOMBUILD@"
 
 
 #------------------------------------------------------------------------
@@ -238,6 +239,11 @@ copyFiles() {
     cp -df $BuiltFBDir/lib/libfbclient.so* ${TargetDir}@FB_LIBDIR@
     cp -f $BuiltFBDir/lib/libib_util.so ${TargetDir}@FB_LIBDIR@/libib_util.so
 
+	if [ "$TomBuild" = "Y" ]; then
+		makeDirs @FB_LIBDIR@/.tm
+		cp -df $BuildRootDir/extern/libtommath/.libs/libtommath.so* ${TargetDir}@FB_LIBDIR@/.tm
+	fi
+
 	chmod 0755 ${TargetDir}@FB_LIBDIR@/*.so*
 
 	#plugins
diff --git a/builds/install/posix-common/posixLibrary.sh.in b/builds/install/posix-common/posixLibrary.sh.in
index 7e4acafe88..c7910eaaad 100644
--- a/builds/install/posix-common/posixLibrary.sh.in
+++ b/builds/install/posix-common/posixLibrary.sh.in
@@ -164,10 +164,22 @@ missingLibrary() {
 }
 
 
+#------------------------------------------------------------------------
+# Check library presence, errorexit when missing
+
+checkLibrary() {
+	libName=${1}
+	haveLibrary $libName || missingLibrary $libName
+}
+
+
 #------------------------------------------------------------------------
 # Make sure we have required libraries installed
 checkLibraries() {
-	haveLibrary tommath || missingLibrary tommath
+	if [ "@TOMBUILD@" != "Y" ]
+	then
+		checkLibrary tommath
+	fi
 }
 
 
@@ -583,8 +595,10 @@ createLinksForBackCompatibility() {
 
 createLinksInSystemLib() {
 	LibDir=`CorrectLibDir @libdir@`
-
+	tommath=libtommath.@SHRLIB_EXT@
+	tomdir=@FB_LIBDIR@/.tm
     origDirLinksInSystemLib=`pwd`
+
     cd @FB_LIBDIR@
 	Libraries=`echo libfbclient.@SHRLIB_EXT@* libib_util.@SHRLIB_EXT@`
 
@@ -594,7 +608,23 @@ createLinksInSystemLib() {
 		safeLink @FB_LIBDIR@/$l .$LibDir/$l ${MANIFEST_TXT}
 	done
 
+	if [ -d $tomdir ]; then
+		cd $tomdir
+		Libraries=""
+		if [ ! -f $LibDir/$tommath ]; then
+			Libraries=`echo ${tommath}*`
+		fi
+
+		cd /
+		for l in $Libraries
+		do
+			safeLink @FB_LIBDIR@/.tm/$l .$LibDir/$l ${MANIFEST_TXT}
+		done
+	fi
+
     cd $origDirLinksInSystemLib
+
+	reconfigDynamicLoader
 }
 
 #------------------------------------------------------------------------
diff --git a/builds/install/posix-common/postuninstall.sh.in b/builds/install/posix-common/postuninstall.sh.in
index e46e8a2004..2b3311e861 100644
--- a/builds/install/posix-common/postuninstall.sh.in
+++ b/builds/install/posix-common/postuninstall.sh.in
@@ -36,3 +36,5 @@ if [ -d $PidDir ]
 then
     rm -rf $PidDir
 fi
+
+reconfigDynamicLoader
diff --git a/builds/posix/Makefile.in b/builds/posix/Makefile.in
index 09f78d78f8..0097f69fde 100644
--- a/builds/posix/Makefile.in
+++ b/builds/posix/Makefile.in
@@ -126,6 +126,12 @@ extern:
 	$(MAKE) -C $(ROOT)/extern/btyacc
 	$(MAKE) -C $(ROOT)/extern/cloop TARGET=release WITH_FPC=0 BUILD_DIR=$(TMP_ROOT)/cloop OUT_DIR=$(GEN_ROOT)/$(TARGET)/cloop
 
+ifeq ($(TOMBUILD_FLG),Y)
+	$(MAKE) -C $(ROOT)/extern/libtommath -f makefile.shared
+	ln -sf $(TOMMATH_SO).$(TOMMATH_VER) $(LIB)
+	ln -sf $(TOMMATH_SO) $(LIB)
+endif
+
 ifeq ($(STD_EDITLINE),false)
 ifeq ($(EDITLINE_FLG),Y)
 	$(MAKE) -f $(GEN_ROOT)/Makefile.extern.editline
diff --git a/builds/posix/make.defaults b/builds/posix/make.defaults
index fb96fad291..f93ad7155b 100755
--- a/builds/posix/make.defaults
+++ b/builds/posix/make.defaults
@@ -48,6 +48,7 @@ LNG_ROOT=$(ROOT)/lang_helpers
 EXA_ROOT=$(ROOT)/examples
 
 IsCross=@IS_CROSS@
+TOMBUILD_FLG=@TOMBUILD@
 
 FB_BUILD=$(GEN_ROOT)/$(TARGET)/firebird
 ifeq ($(IsCross), Y)
@@ -249,6 +250,12 @@ endif
 IbUtilLibraryName = $(LIB_PREFIX)ib_util.$(SHRLIB_EXT)
 LIBIBUTIL_SO = $(LIB)/$(IbUtilLibraryName)
 
+# Own tommath support
+TOMMATH=$(ROOT)/extern/libtommath
+TOMMATH_INC=$(TOMMATH)
+TOMMATH_SO=$(TOMMATH)/.libs/libtommath.so
+TOMMATH_VER=0
+
 # LINKER OPTIONS
 #
 
diff --git a/builds/posix/make.rules b/builds/posix/make.rules
index 0d1769b5a5..e48228ef1d 100644
--- a/builds/posix/make.rules
+++ b/builds/posix/make.rules
@@ -34,6 +34,10 @@
 # Please don't use compiler/platform specific flags here - nmcc 02-Nov-2002
 WFLAGS =-I$(SRC_ROOT)/include/gen -I$(SRC_ROOT)/include $(CPPFLAGS)
 
+ifeq ($(TOMBUILD_FLG),Y)
+  WFLAGS += -I$(TOMMATH_INC)
+endif
+
 ifeq ($(TARGET),Release)
   WFLAGS += $(PROD_FLAGS)
 else
diff --git a/configure.ac b/configure.ac
index 9c2c22269b..0dd5403c7c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -508,6 +508,12 @@ AC_ARG_WITH(cross-build,
    IS_CROSS=Y])
 AC_SUBST(IS_CROSS)
 
+TOMBUILD=N
+AC_ARG_WITH(builtin-tommath,
+  [  --with-builtin-tommath  build libtommath library from firebird tree],
+  [TOMBUILD=Y])
+AC_SUBST(TOMBUILD)
+
 dnl Avoid dumb '-g -O2' autoconf's default
 dnl Debugging information and optimization flags should be set in prefix.$platform file
 dnl Should be replaced with AC_PROG_GCC_DEFAULT_FLAGS() when available
@@ -765,11 +771,17 @@ dnl setting ICU_OK here is done to only avoid default action
 AC_CHECK_LIB(icuuc, main, ICU_OK=yes, AC_MSG_ERROR(ICU support not found - please install development ICU package))
 
 dnl check for tommath presence
-XE_SAVE_ENV()
-LIBS=
-AC_CHECK_HEADER(tommath.h,,AC_MSG_ERROR(Include file for tommath not found - please install development tommath package))
-AC_CHECK_LIB(tommath, mp_init, MATHLIB=-ltommath, AC_MSG_ERROR(Library tommath not found - please install development tommath package))
-XE_RESTORE_ENV()
+if test "$TOMBUILD" = "Y"; then
+	MATHLIB=-ltommath
+else
+	AC_CHECK_HEADER(tommath.h,,
+		AC_MSG_ERROR(Include file for tommath not found - please install development tommath package or use --with-builtin-tommath))
+	XE_SAVE_ENV()
+	LIBS=
+	AC_CHECK_LIB(tommath, mp_init, MATHLIB=-ltommath,
+		AC_MSG_ERROR(Library tommath not found - please install development tommath package or use --with-builtin-tommath))
+	XE_RESTORE_ENV()
+fi
 AC_SUBST(MATHLIB)
 
 dnl Check for libraries
diff --git a/extern/libtommath/.gitignore b/extern/libtommath/.gitignore
index f3868f90cd..86cbfa9b3b 100644
--- a/extern/libtommath/.gitignore
+++ b/extern/libtommath/.gitignore
@@ -1,2 +1,5 @@
 lib/
 temp/
+*.o
+*.l*
+.libs/
diff --git a/extern/libtommath/makefile.shared b/extern/libtommath/makefile.shared
index f17bbbd484..c0d159caf8 100644
--- a/extern/libtommath/makefile.shared
+++ b/extern/libtommath/makefile.shared
@@ -83,7 +83,7 @@ bn_mp_to_signed_bin_n.o bn_mp_to_unsigned_bin_n.o
 objs: $(OBJECTS)
 
 $(LIBNAME):  $(OBJECTS)
-	libtool --mode=link gcc *.lo -o $(LIBNAME) -rpath $(LIBPATH) -version-info $(VERSION)
+	libtool --mode=link --tag=CC gcc *.lo -o $(LIBNAME) -rpath $(LIBPATH) -version-info $(VERSION)
 
 install: $(LIBNAME)
 	install -d -g $(GROUP) -o $(USER) $(DESTDIR)$(LIBPATH)