Disable strict check for PHP 5.6. Still just as valid code, but stopping build.

Added -Wextra CFLAG. Fixed issues that arose from turning that flag on.

Updated CFLAGS to warn about implicit function declarations, and fixed the revealed issues.

Adding missing functions and constants.

* Imagick::autoGammaImage([int channel = CHANNEL_ALL])
* Imagick::autoOrient()
* Imagick::compositeImageGravity(Imagick $image, int COMP

Adding missing functions and constants.

* Imagick::autoGammaImage([int channel = CHANNEL_ALL])
* Imagick::autoOrient()
* Imagick::compositeImageGravity(Imagick $image, int COMPOSITE_CONSTANT, int GRAVITY_CONSTANT)
* Imagick::localContrastImage(float radius, float strength)
* Imagick::DIRECTION_LEFT_TO_RIGHT
* Imagick::DIRECTION_RIGHT_TO_LEFT
* Imagick::SPARSECOLORMETHOD_MANHATTAN
* ImagickDraw::getOpacity() : float
* ImagickDraw::setOpacity(float opacity) :bool
* ImagickDraw::getFontResolution() : array
* ImagickDraw::setFontResolution(float x, float y) : bool
* ImagickDraw::getTextDirection() : bool
* ImagickDraw::setTextDirection(int direction) : bool
* ImagickDraw::getBorderColor() : ImagickPixel
* ImagickDraw::setBorderColor(ImagickPixel color) : bool
* ImagickDraw::getDensity() : string|null
* ImagickDraw::setDensity(string density_string) : bool
* ImagickPixel::setColorFromPixel(ImagickPixel $srcPixel) : bool

show more ...

Enabled -Wall and fixed various small issues. Added test for progress monitor via callback, which is broken in 7.

Moved setting CFLAGS out of travis script, to allow it to be more flexible and not forced onto a single line.