/usr/bin/ld: cannot find -llibboost_filesystem
So I'm trying to compile my app (note: my first makefile) and I've verified the libraries are in /usr/lib so I'm really not sure at all why I'm getting this errors when I run make:

    Linking bin/Pathing...
    /usr/bin/ld: cannot find -llibboost_filesystem
    /usr/bin/ld: cannot find -llibboost_thread-mt
    /usr/bin/ld: cannot find -llibboost_system
    collect2: ld returned 1 exit status
    make: *** [bin/Pathing] Error 1

The relevant line: 
LDFLAGS  = -L/usr/lib -llibboost_filesystem -llibboost_thread-mt -llibboost_system

Do you see anything glaringly wrong here?  (Trying to compile on 64-bit Ubuntu 11.10 if it matters...)

The entire makefile for those curious:

    # this variable is used to set the executable name
    APP      = Pathing
    
    # this  variable is used to set the extension of files to be compiled
    SRCEXT   = cpp
    
    #this variable sets to top files hierarchy
    SRCDIR   = Pathing
    
    # intermediate object files will be organized under this directory (value of OBJDIR)
    OBJDIR   = obj
    
    #Executable file will be under $BINDIR
    BINDIR   = bin
    
    #This command will look for all source files to be compiled
    SRCS    := $(shell find $(SRCDIR) -name '*.$(SRCEXT)')
    
    #this command is used to determine the subdiretories tree
    SRCDIRS := $(shell find . -name '*.$(SRCEXT)' -exec dirname {} \; | uniq)
    
    
    OBJS    := $(patsubst %.$(SRCEXT),$(OBJDIR)/%.o,$(SRCS))
    
    DEBUG    = -g
    INCLUDES = -I./libs/PlistCpp/src -I/usr/local/include/thrift -I./thrift/gen-cpp  -I./Pathing  -I./libs/Detour -I./libs/DetourCrowd -I./libs/DetourTileCache
    CFLAGS   = -DHAVE_NETINET_IN_H -Wall -pedantic -ansi -c $(DEBUG) $(INCLUDES)
    LDFLAGS  = -L/usr/lib -llibboost_filesystem -llibboost_thread-mt -llibboost_system         
    
    ifeq ($(SRCEXT), cpp)
    CC       = $(CXX)
    else
    CFLAGS  += -std=gnu99
    endif
    
    .PHONY: all clean distclean
    
    
    all: $(BINDIR)/$(APP)
    
    $(BINDIR)/$(APP): buildrepo $(OBJS)
            @mkdir -p `dirname $@`
            @echo "Linking $@..."
            @$(CC) $(OBJS) $(LDFLAGS) -o $@
    
    $(OBJDIR)/%.o: %.$(SRCEXT)
            @echo "Generating dependencies for $<..."
            @$(call make-depend,$<,$@,$(subst .o,.d,$@))
            @echo "Compiling $<..."
            @$(CC) $(CFLAGS) $< -o $@
    
    clean:
            $(RM) -r $(OBJDIR)
    
    distclean: clean
            $(RM) -r $(BINDIR)
    
    buildrepo:
            @$(call make-repo)
    
    define make-repo
       for dir in $(SRCDIRS); \
       do \
            mkdir -p $(OBJDIR)/$$dir; \
       done
    endef
    
    
    # usage: $(call make-depend,source-file,object-file,depend-file)
    define make-depend
      $(CC) -MM       \
            -MF $3    \
            -MP       \
            -MT $2    \
            $(CFLAGS) \
            $1
    endef

And here is an example which shows the files in /usr/lib:

    -rw-r--r--  1 root root   48666 2011-06-03 16:30 libboost_system.a
    lrwxrwxrwx  1 root root      17 2011-06-03 16:30 libboost_system-mt.a -> libboost_system.a
    lrwxrwxrwx  1 root root      25 2011-06-03 16:30 libboost_system-mt.so -> libboost_system.so.1.46.1
    lrwxrwxrwx  1 root root      25 2011-06-03 16:30 libboost_system.so -> libboost_system.so.1.46.1
    -rw-r--r--  1 root root   14568 2011-06-03 16:30 libboost_system.so.1.46.1
/usr/bin/ld: cannot find -llibboost_filesystem
===

So I'm trying to compile my app (note: my first makefile) and I've verified the libraries are in /usr/lib so I'm really not sure at all why I'm getting this errors when I run make:

    Linking bin/Pathing...
    /usr/bin/ld: cannot find -llibboost_filesystem
    /usr/bin/ld: cannot find -llibboost_thread-mt
    /usr/bin/ld: cannot find -llibboost_system
    collect2: ld returned 1 exit status
    make: *** [bin/Pathing] Error 1

The relevant line: 
LDFLAGS  = -L/usr/lib -llibboost_filesystem -llibboost_thread-mt -llibboost_system

Do you see anything glaringly wrong here?  (Trying to compile on 64-bit Ubuntu 11.10 if it matters...)

The entire makefile for those curious:

    # this variable is used to set the executable name
    APP      = Pathing
    
    # this  variable is used to set the extension of files to be compiled
    SRCEXT   = cpp
    
    #this variable sets to top files hierarchy
    SRCDIR   = Pathing
    
    # intermediate object files will be organized under this directory (value of OBJDIR)
    OBJDIR   = obj
    
    #Executable file will be under $BINDIR
    BINDIR   = bin
    
    #This command will look for all source files to be compiled
    SRCS    := $(shell find $(SRCDIR) -name '*.$(SRCEXT)')
    
    #this command is used to determine the subdiretories tree
    SRCDIRS := $(shell find . -name '*.$(SRCEXT)' -exec dirname {} \; | uniq)
    
    
    OBJS    := $(patsubst %.$(SRCEXT),$(OBJDIR)/%.o,$(SRCS))
    
    DEBUG    = -g
    INCLUDES = -I./libs/PlistCpp/src -I/usr/local/include/thrift -I./thrift/gen-cpp  -I./Pathing  -I./libs/Detour -I./libs/DetourCrowd -I./libs/DetourTileCache
    CFLAGS   = -DHAVE_NETINET_IN_H -Wall -pedantic -ansi -c $(DEBUG) $(INCLUDES)
    LDFLAGS  = -L/usr/lib -llibboost_filesystem -llibboost_thread-mt -llibboost_system         
    
    ifeq ($(SRCEXT), cpp)
    CC       = $(CXX)
    else
    CFLAGS  += -std=gnu99
    endif
    
    .PHONY: all clean distclean
    
    
    all: $(BINDIR)/$(APP)
    
    $(BINDIR)/$(APP): buildrepo $(OBJS)
            @mkdir -p `dirname $@`
            @echo "Linking $@..."
            @$(CC) $(OBJS) $(LDFLAGS) -o $@
    
    $(OBJDIR)/%.o: %.$(SRCEXT)
            @echo "Generating dependencies for $<..."
            @$(call make-depend,$<,$@,$(subst .o,.d,$@))
            @echo "Compiling $<..."
            @$(CC) $(CFLAGS) $< -o $@
    
    clean:
            $(RM) -r $(OBJDIR)
    
    distclean: clean
            $(RM) -r $(BINDIR)
    
    buildrepo:
            @$(call make-repo)
    
    define make-repo
       for dir in $(SRCDIRS); \
       do \
            mkdir -p $(OBJDIR)/$$dir; \
       done
    endef
    
    
    # usage: $(call make-depend,source-file,object-file,depend-file)
    define make-depend
      $(CC) -MM       \
            -MF $3    \
            -MP       \
            -MT $2    \
            $(CFLAGS) \
            $1
    endef

And here is an example which shows the files in /usr/lib:

    -rw-r--r--  1 root root   48666 2011-06-03 16:30 libboost_system.a
    lrwxrwxrwx  1 root root      17 2011-06-03 16:30 libboost_system-mt.a -> libboost_system.a
    lrwxrwxrwx  1 root root      25 2011-06-03 16:30 libboost_system-mt.so -> libboost_system.so.1.46.1
    lrwxrwxrwx  1 root root      25 2011-06-03 16:30 libboost_system.so -> libboost_system.so.1.46.1
    -rw-r--r--  1 root root   14568 2011-06-03 16:30 libboost_system.so.1.46.1