diff --git a/INCLUDE/counter.h b/INCLUDE/counter.h
index 92719a1..103ba94 100644
--- a/INCLUDE/counter.h
+++ b/INCLUDE/counter.h
@@ -51,7 +51,11 @@
 
 typedef struct {
   int             value;
+#ifdef NOSPINLOCKS
+  pthread_mutex_t    lock;
+#else
   pthread_spinlock_t lock;
+#endif
 } counter_t;
 
 counter_t *PMR_create_counter(int init_value);
diff --git a/INCLUDE/queue.h b/INCLUDE/queue.h
index 54ad939..b4da63b 100644
--- a/INCLUDE/queue.h
+++ b/INCLUDE/queue.h
@@ -62,7 +62,11 @@ typedef struct {
   int             num_tasks;
   task_t          *head;
   task_t          *back;
+#ifdef NOSPINLOCKS
+  pthread_mutex_t    lock;
+#else
   pthread_spinlock_t lock;
+#endif
 } queue_t;
 
 
diff --git a/INSTALL/make.inc.gnu b/INSTALL/make.inc.gnu
index 7359e14..73a6b39 100644
--- a/INSTALL/make.inc.gnu
+++ b/INSTALL/make.inc.gnu
@@ -16,6 +16,10 @@ ARFLAGS = rcs
 # to 0 by default
 COMPLEX_SUPPORT = 0
 
-# Compile routines without adding necessary LAPACK routines 
-# to 'libmrrr.a'; default = 0
-NOLAPACK = 0
\ No newline at end of file
+# To build 'libmrrr.a' without adding necessary LAPACK routines 
+# for the to the archive set value to 0; default value is 1
+INCLAPACK = 1
+
+# On some systems 'spinlocks' are not supported, therefore 
+# here the flag to use 'mutexes' instead; default value is 1
+SPINLOCK_SUPPORT = 1
\ No newline at end of file
diff --git a/INSTALL/make.inc.ibm b/INSTALL/make.inc.ibm
index adeacaa..0adbd39 100644
--- a/INSTALL/make.inc.ibm
+++ b/INSTALL/make.inc.ibm
@@ -16,6 +16,10 @@ ARFLAGS = rcs
 # to 0 by default
 COMPLEX_SUPPORT = 0
 
-# Compile routines without adding necessary LAPACK routines 
-# to 'libmrrr.a'; default = 0
-NOLAPACK = 0
+# To build 'libmrrr.a' without adding necessary LAPACK routines 
+# for the to the archive set value to 0; default value is 1
+INCLAPACK = 1
+
+# On some systems 'spinlocks' are not supported, therefore 
+# here the flag to use 'mutexes' instead; default value is 1
+SPINLOCK_SUPPORT = 1
\ No newline at end of file
diff --git a/INSTALL/make.inc.intel b/INSTALL/make.inc.intel
index 79bbd1c..d6a699d 100644
--- a/INSTALL/make.inc.intel
+++ b/INSTALL/make.inc.intel
@@ -4,7 +4,7 @@ FC = ifort
 
 # Compiler flags
 CFLAGS = -pthread -O3 -restrict
-FFLAGS = -nofor-main -O3
+FFLAGS = -nofor-main -O3 -assume underscore
 
 # Archiver and flags used when building the archive
 AR = /usr/bin/ar 
@@ -16,6 +16,10 @@ ARFLAGS = rcs
 # to 0 by default
 COMPLEX_SUPPORT = 0
 
-# Compile routines without adding necessary LAPACK routines 
-# to 'libmrrr.a'; default = 0
-NOLAPACK = 0
+# To build 'libmrrr.a' without adding necessary LAPACK routines 
+# for the to the archive set value to 0; default value is 1
+INCLAPACK = 1
+
+# On some systems 'spinlocks' are not supported, therefore 
+# here the flag to use 'mutexes' instead; default value is 1
+SPINLOCK_SUPPORT = 1
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 37dabb3..8f70b89 100644
--- a/Makefile
+++ b/Makefile
@@ -9,12 +9,16 @@ ifeq ($(COMPLEX_SUPPORT),1)
  CFLAGS += -DCOMPLEX_SUPPORTED
 endif
 
+ifeq ($(SPINLOCK_SUPPORT),0)
+ CFLAGS += -DNOSPINLOCKS
+endif
+
 # Source files
 HEADERS := $(foreach DIR,$(DIRS),$(wildcard $(DIR)/*.h))
 CSRCS   := $(foreach DIR,$(DIRS),$(wildcard $(DIR)/*.c))
 COBJS = $(CSRCS:.c=.o)
 
-ifeq ($(NOLAPACK),1)
+ifeq ($(INCLAPACK),0)
  FSRCS   := $(foreach DIR,$(DIRS),$(wildcard $(DIR)/odscal.f))
  FOBJS = $(FSRCS:.f=.o)
 else
diff --git a/SRC/counter.c b/SRC/counter.c
index 5327383..f59c58d 100644
--- a/SRC/counter.c
+++ b/SRC/counter.c
@@ -59,7 +59,11 @@ counter_t *PMR_create_counter(int init_value)
   counter = (counter_t *) malloc( sizeof(counter_t) );
   
   counter->value = init_value;
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_init(&counter->lock, NULL);
+#else
   info = pthread_spin_init(&counter->lock, PTHREAD_PROCESS_PRIVATE);
+#endif
   assert(info == 0);
   
   return(counter);
@@ -69,7 +73,11 @@ counter_t *PMR_create_counter(int init_value)
 
 inline void PMR_destroy_counter(counter_t *counter)
 {
+#ifdef NOSPINLOCKS
+  pthread_mutex_destroy(&counter->lock);
+#else
   pthread_spin_destroy(&counter->lock);
+#endif
   free(counter);
 }
 
@@ -79,12 +87,20 @@ inline int PMR_get_counter_value(counter_t *counter)
 {
   int value, info;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_lock(&counter->lock);
+#else
   info = pthread_spin_lock(&counter->lock);
+#endif
   assert(info == 0);
 
   value = counter->value;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_unlock(&counter->lock);
+#else
   info = pthread_spin_unlock(&counter->lock);
+#endif
   assert(info == 0);
 
   return(value);
@@ -96,12 +112,20 @@ inline int PMR_set_counter_value(counter_t *counter, int value)
 {
   int info;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_lock(&counter->lock);
+#else
   info = pthread_spin_lock(&counter->lock);
+#endif
   assert(info == 0);
 
   counter->value = value;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_unlock(&counter->lock);
+#else
   info = pthread_spin_unlock(&counter->lock);
+#endif
   assert(info == 0);
   
   return(value);
@@ -113,13 +137,21 @@ inline int PMR_decrement_counter(counter_t *counter, int amount)
 {
   int value, info;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_lock(&counter->lock);
+#else
   info = pthread_spin_lock(&counter->lock);
+#endif
   assert(info == 0);
 
   counter->value -= amount;
   value = counter->value;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_unlock(&counter->lock);
+#else
   info = pthread_spin_unlock(&counter->lock);
+#endif
   assert(info == 0);
 
   return(value);
diff --git a/SRC/queue.c b/SRC/queue.c
index 521c76d..73a5a97 100644
--- a/SRC/queue.c
+++ b/SRC/queue.c
@@ -65,7 +65,11 @@ queue_t *PMR_create_empty_queue(void)
   queue->head      = NULL;
   queue->back      = NULL;
   
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_init(&queue->lock, NULL);
+#else
   info = pthread_spin_init(&queue->lock, PTHREAD_PROCESS_PRIVATE);
+#endif
   assert(info == 0);
 
   return(queue);
@@ -75,7 +79,11 @@ queue_t *PMR_create_empty_queue(void)
 
 void PMR_destroy_queue(queue_t *queue)
 {
+#ifdef NOSPINLOCKS
+  pthread_mutex_destroy(&queue->lock);
+#else
   pthread_spin_destroy(&queue->lock);
+#endif
   free(queue);
 }
 
@@ -85,12 +93,20 @@ int PMR_get_num_tasks(queue_t *queue)
 {
   int info, num_tasks;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_lock(&queue->lock);
+#else
   info = pthread_spin_lock(&queue->lock);
+#endif
   assert(info == 0);
 
   num_tasks = queue->num_tasks;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_unlock(&queue->lock);
+#else
   info = pthread_spin_unlock(&queue->lock);
+#endif
   assert(info == 0);
 
   return(num_tasks);
@@ -126,7 +142,11 @@ int PMR_insert_task_at_back(queue_t *queue, task_t *task)
 {
   int info;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_lock(&queue->lock);
+#else
   info = pthread_spin_lock(&queue->lock);
+#endif
   assert(info == 0);
 
   queue->num_tasks++;
@@ -139,7 +159,11 @@ int PMR_insert_task_at_back(queue_t *queue, task_t *task)
     queue->back->next = task;
   queue->back = task;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_unlock(&queue->lock);
+#else
   info = pthread_spin_unlock(&queue->lock);
+#endif
   assert(info == 0);
   
   return(info);
@@ -152,7 +176,11 @@ task_t *PMR_remove_task_at_front(queue_t *queue)
   int    info;
   task_t *task;
   
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_lock(&queue->lock);
+#else
   info = pthread_spin_lock(&queue->lock);
+#endif
   assert(info == 0);
   
   task = queue->head;
@@ -171,7 +199,11 @@ task_t *PMR_remove_task_at_front(queue_t *queue)
     }
   }
   
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_unlock(&queue->lock);
+#else
   info = pthread_spin_unlock(&queue->lock);
+#endif
   assert(info == 0);
   
   return(task);
@@ -185,7 +217,11 @@ task_t *PMR_remove_task_at_back (queue_t *queue)
   int    info;
   task_t *task;
 
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_lock(&queue->lock);
+#else
   info = pthread_spin_lock(&queue->lock);
+#endif
   assert(info == 0);
   
   task = queue->back;
@@ -204,7 +240,11 @@ task_t *PMR_remove_task_at_back (queue_t *queue)
     }
   }
   
+#ifdef NOSPINLOCKS
+  info = pthread_mutex_unlock(&queue->lock);
+#else
   info = pthread_spin_unlock(&queue->lock);
+#endif
   assert(info == 0);
 
   return(task);
diff --git a/make.inc b/make.inc
index 7359e14..73a6b39 100644
--- a/make.inc
+++ b/make.inc
@@ -16,6 +16,10 @@ ARFLAGS = rcs
 # to 0 by default
 COMPLEX_SUPPORT = 0
 
-# Compile routines without adding necessary LAPACK routines 
-# to 'libmrrr.a'; default = 0
-NOLAPACK = 0
\ No newline at end of file
+# To build 'libmrrr.a' without adding necessary LAPACK routines 
+# for the to the archive set value to 0; default value is 1
+INCLAPACK = 1
+
+# On some systems 'spinlocks' are not supported, therefore 
+# here the flag to use 'mutexes' instead; default value is 1
+SPINLOCK_SUPPORT = 1
\ No newline at end of file