diff --git a/m4/ax_mexopts.m4 b/m4/ax_mexopts.m4
index eff7dc0c9..9b51833c6 100644
--- a/m4/ax_mexopts.m4
+++ b/m4/ax_mexopts.m4
@@ -29,25 +29,17 @@ AC_MSG_CHECKING([for options to compile MEX for MATLAB])
 MATLAB_CPPFLAGS="-I$MATLAB/extern/include"
 
 case ${MATLAB_ARCH} in
-  glnx86 | glnxa64)
+  glnxa64)
     MATLAB_DEFS="$MATLAB_DEFS -D_GNU_SOURCE -DNDEBUG"
-    MATLAB_CFLAGS="-fexceptions -fPIC -pthread -g -O2"
-    MATLAB_CXXFLAGS="-fPIC -pthread -g -O2"
+    MATLAB_CFLAGS="-fexceptions -fno-omit-frame-pointer -fPIC -pthread -g -O2"
+    MATLAB_CXXFLAGS="-fno-omit-frame-pointer -fPIC -pthread -g -O2"
     MATLAB_FCFLAGS="-fPIC -g -O2 -fexceptions"
-    MATLAB_LDFLAGS_NOMAP="-shared -Wl,--no-undefined -Wl,-rpath-link,$MATLAB/bin/${MATLAB_ARCH} -L$MATLAB/bin/${MATLAB_ARCH}"
-    MATLAB_LDFLAGS="$MATLAB_LDFLAGS_NOMAP -Wl,--version-script,$MATLAB/extern/lib/${MATLAB_ARCH}/mexFunction.map"
+    MATLAB_LDFLAGS_NOMAP="-shared -Wl,--no-undefined -Wl,-rpath-link,$MATLAB/bin/glnxa64 -L$MATLAB/bin/glnxa64"
+    MATLAB_LDFLAGS="$MATLAB_LDFLAGS_NOMAP -Wl,--version-script,$MATLAB/extern/lib/glnxa64/mexFunction.map"
     MATLAB_LIBS="-lmx -lmex -lmat -lm -lstdc++ -lmwlapack -lmwblas"
-    if test "${MATLAB_ARCH}" = "glnx86"; then
-      MATLAB_DEFS="$MATLAB_DEFS -D_FILE_OFFSET_BITS=64"
-      MATLAB_CFLAGS="$MATLAB_CFLAGS -m32"
-      MATLAB_CXXFLAGS="$MATLAB_CXXFLAGS -m32"
-    else # glnxa64
-      MATLAB_CFLAGS="$MATLAB_CFLAGS -fno-omit-frame-pointer"
-      MATLAB_CXXFLAGS="$MATLAB_CXXFLAGS -fno-omit-frame-pointer"
-    fi
     ax_mexopts_ok="yes"
     ;;
-  win32 | win64)
+  win64)
     MATLAB_CFLAGS="-fexceptions -g -O2"
     MATLAB_CXXFLAGS="-g -O2"
     MATLAB_FCFLAGS="-g -O2 -fexceptions -fno-underscoring"
@@ -57,7 +49,7 @@ case ${MATLAB_ARCH} in
     # The last part about winpthread is a hack to avoid dynamically linking
     # against libwinpthread DLL (which is pulled in by libstdc++, even without
     # using threads, since we are using the POSIX threads version of MinGW)
-    MATLAB_LDFLAGS_NOMAP="-static-libgcc -static-libstdc++ -static-libgfortran -Wl,-Bstatic,--whole-archive -lquadmath -Wl,-Bdynamic,--no-whole-archive -shared -L$MATLAB/bin/${MATLAB_ARCH} -Wl,-Bstatic,--whole-archive -lwinpthread -Wl,-Bdynamic,--no-whole-archive"
+    MATLAB_LDFLAGS_NOMAP="-static-libgcc -static-libstdc++ -static-libgfortran -Wl,-Bstatic,--whole-archive -lquadmath -Wl,-Bdynamic,--no-whole-archive -shared -L$MATLAB/bin/win64 -Wl,-Bstatic,--whole-archive -lwinpthread -Wl,-Bdynamic,--no-whole-archive"
     MATLAB_LDFLAGS="$MATLAB_LDFLAGS_NOMAP \$(abs_top_srcdir)/mex.def"
     MATLAB_LIBS="-lmex -lmx -lmat -lmwlapack -lmwblas"
     # Hack for static linking of libgomp, needed for OpenMP
diff --git a/m4/ax_slicot.m4 b/m4/ax_slicot.m4
index 37bfaa843..196255531 100644
--- a/m4/ax_slicot.m4
+++ b/m4/ax_slicot.m4
@@ -5,7 +5,7 @@ dnl
 dnl AX_SLICOT([matlab])
 dnl AX_SLICOT([octave])
 dnl
-dnl Copyright © 2012-2019 Dynare Team
+dnl Copyright © 2012-2021 Dynare Team
 dnl
 dnl This file is part of Dynare.
 dnl
@@ -45,20 +45,7 @@ AC_DEFUN([AX_SLICOT],
   if test "$1" = matlab; then
     LDFLAGS="$LDFLAGS $MATLAB_LDFLAGS_NOMAP $LDFLAGS_SLICOT"
 
-    case ${MATLAB_ARCH} in
-       glnxa64 | win64 | maci64)
-         AX_COMPARE_VERSION([$MATLAB_VERSION], [ge], [7.8], [use_64_bit_indexing=yes], [use_64_bit_indexing=no])
-         ;;
-       *)
-         use_64_bit_indexing=no
-         ;;
-    esac
-
-    if test "$use_64_bit_indexing" = yes; then
-       AC_CHECK_LIB([slicot64_pic], [$sb02od], [LIBADD_SLICOT="-lslicot64_pic"], [has_slicot=no], [$MATLAB_LIBS])
-    else
-       AC_CHECK_LIB([slicot_pic], [$sb02od], [LIBADD_SLICOT="-lslicot_pic"], [has_slicot=no], [$MATLAB_LIBS])
-    fi
+    AC_CHECK_LIB([slicot64_pic], [$sb02od], [LIBADD_SLICOT="-lslicot64_pic"], [has_slicot=no], [$MATLAB_LIBS])
   else
     LDFLAGS="$LDFLAGS $($MKOCTFILE -p LFLAGS) $LDFLAGS_SLICOT"
     # Fallback on libslicot_pic if dynamic libslicot not found